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Light Rail or Automatic Guided Transit

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The quality and attractiveness of urban public transport has been improved by several technological innovations over the past twenty years. Operating conditions have been transformed, with improved safety and flexibility ; adaptation to the needs of passengers and operators can be ensured owing to the possibilities offered by automation. Light rail and automatic guided transit systems present intermediate characteristics between those of buses riding on shared right of way and those of conventional metros on segregated right of way, from the point of view of investment costs, Light Rail Transit can also, more and less, offer similar service and operating costs. In this paper, the two types of new transit systems operated in France for more than fifteen years : Light Rail and Automatic Guided Transit are presented 2 .
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1F. Kühn
FRENCH – KOREAN MEETING
URBAN TRANSIT
Seoul, 16 & 17 April, 2003
Light Rail or Automatic Guided Transit
Francis Kühn1
Abstract
The quality and attractiveness of urban public transport has been improved by
several technological innovations over the past twenty years. Operating conditions
have been transformed, with improved safety and flexibility ; adaptation to the needs
of passengers and operators can be ensured owing to the possibilities offered by
automation. Light rail and automatic guided transit systems present intermediate
characteristics between those of buses riding on shared right of way and those of
conventional metros on segregated right of way, from the point of view of investment
costs, Light Rail Transit can also, more and less, offer similar service and operating
costs. In this paper, the two types of new transit systems operated in France for more
than fifteen years : Light Rail and Automatic Guided Transit are presented2.
1. Light Rail Transit
In 1975, there were around 300 urban tramways networks in the world.
Nowadays, this had grown to more than 400 networks of Light rails or streetcars
operating in 50 countries on all the continents. More than 100 lines are under studies
all around the world.
1 INRETS, 2 Avenue Malleret-Joinville ARCUEIL 94114 Cedex, FRANCE E-mail::Kuhn@inrets.fr
2 LRT, presented here is the Nantes network system which is in service for twelve years;
AGT, or fully automatic system, presented here is the VAL of Lille which is in service for fourteen years.
2F. Kühn
Source : SEMITAN, Métro léger de Nantes
1.1 Infrastructures of Light Rail Transit
Urban transit systems use only a minimal area of ground for parking and
maximise the capacity of the running lanes, they have a smaller impact on space
uptake and the environment. The quality of service and capacity of light rail transit
systems will depend on the type and size of the public transport vehicle, the means
used to establish right of way segregation and the degree of segregation in town
centres. When there is no land in the centre of the city, it becomes necessary to
implement big public works by putting the tracks underground, which results in the
loss of some advantages of Light Rail Transit, from the investment point of view.
1.2 The choice of type of right of way and investment
We imagine the influence of the choice of a type of site on the total investment
of the Light Rail Transit system. This choice also influences the offered capacity at
peak hours. Histogram 1 below shows some civil engineering costs of Light Rail
Transit (per km of double track without rails and energy) according to whether part
of the line is on surface, underground or elevated.
3F. Kühn
Histogram : 1 Civil engineering costs of LRT
Cost US $/km
Mix.traffic1
Mix.traffic2
Excl. RoW1
Excl. RoW2
Elevated1
Elevated2
Underground1
Underground2
0
5
10
15
20
25
30
35
40
45
Million US $
Type of RoW
Civil Engineering Costs per km
Mix.traffic
1
Mix.traffic
2
Excl. RoW1
Excl. RoW2
Source : (Kühn,1997), (Kühn,2001), valeur 2002 1 US $ = 1 Euro
1.3 Operation speed
The operation speeds of a Light Rail Transit is generally lower than those of an
Automatic Guided Transit for several reasons like the delays due to the traffic
conditions, the waiting time in front of the lights at the cross-roads, the limitations of
the speed due to the insertion problems of the track have a bad influence, the stop
time, the order speed (desired speed) reached is lower than those reached on long
inter-station links.
1.4 Operating frequency and quality of service
The frequency of passage depends on several parameters such as the vehicle's
monitoring speed, the braking ratio, the level of safety, the response time of the
braking-acceleration system, the station, the stop time which depends on the number
of boarding-alighting passengers, and the random conflicts along the line .
This frequency also depends on the signalisation : on the surface, the Light Rail
adopts the sight seeing driving, near the cross-roads the lights are influenced or
directly controlled by the trains in the frame of the priority which is generally given to
them. In the underground sections, they generally use automatic block signals,
completed by automatic emergency braking, devices controlling the trains going
through the signals and controlling the speed, in case of a behaviour engaging the
safety : there is a reduction of the flow in relation with those permitted with running at
sight, this heterogeneity of flow results in an obligation to foresee regulation devices
when there is a common underground section in the city centre.
Light Rail operating systems can be made with the help of operational control
systems allowing postponement of departures according to frequency3 and to give
3 Generally in France the frequency between two trains at the peak hour is 4 to 5 minutes and 7 to 10
minutes at off-peak hours.
4F. Kühn
the drivers the necessary information to regulate their speed in relation to the
scheduled trip times. Thus, thanks to the separated ROW4, the priority at signalised
junctions, the adapted signalisation to the type of running site, LRT can offer quality
of service with regularity, punctuality, and safety comparable to that of the metro since
the investments would be important.
1.5 Capacity
At peak hour, with an interval of 4 minutes the offer can be of 2600 phd5 6 the
operation can be done by multiple units of up to 2 units that brings the capacity to
5200 phd. To obtain more capacity we must reduce the interval that is to say improve
the signalisation, the segregation of the site in relation to the general traffic and
increase the number of cars per train.
2. Automatic Guided Transit
Since 1981, about twenty automatic urban transport of conventional type
systems are under operation in actual urban centre services and several systems are
planned or under construction. In all the cases, these are systems running on
segregated right of way, fully automated, with quite different vehicle characteristics.
The application of fully automated driverless operation to the new transit
systems is the consequence of a research of technical performances (high speeds,
reducing intervals between trains, increasing safety) not possible with manually
operated trains. Indeed, at the peak hours on the urban metro of Paris and other
networks in the world, most of the lines have been manually operated for twenty years
yet automatically at least at peak hours, that is to say at those where operation must be
the most efficient and where drivers would have to apply more concentration than
humanly possible.
The user benefits from the high frequency brought by full automation, avoiding
long waiting times in station. This quality gives further attraction to public transport.
In addition, this high frequency also can be obtained at off-peak hours by cutting
trains between peak and off-peak hours which brings operation supplementary
flexibility. High frequency of passage has another advantage on civil engineering
costs of transit systems : at equal capacity the light rail (TFS7 type) running with 3
unit trains every 4 minutes offers a capacity of 7800 phd., the AGT ( VAL type)
running with 1 unit train with an interval of 72 seconds offers a 8000 phd. capacity.
In the first case the platform length is 90 m, in the second case the platform length is
26 m.
The innovations brought to the traditional modes of transport system have
greatly spurred the improvement of the networks productivity. The rapid progress of
technologies linked to the electronics and computing leads to increased gains in
productivity bestowing on the public transport networks a growing tendency to
automation.
The objectives to minimise the costs of a mean of transport, adapted to a
demand whose importance and structure normally justify a metro, all by giving to
users a high service quality have permitted to define for Lille the small gauge of
VAL's system, its short passing headway at the peak hour and the technical and
4 ROW : Right of Way
5 phd : places per hour per direction
6 At a normal load a LRV (Grenoble type) carries around 175 pass. and 240 pass. (6 pass./m2).
7 TFS : Tramway Français Standard
5F. Kühn
economical necessity to conceive its automatic integral control.
This type of driverless automation on board, has given place to particular
technical solutions which would not be the same for other metros manually operated :
ie. the landing doors on the platforms, the numerous redundancies of certain
equipment items allowing to guaranty a very high availability without need of an
immediate human intervention and the necessity to highly develop the means of
monitoring and communication.
Source : MetroPlanet, SMAT, Métro de Toulouse
2.1 Infrastructures of Automated Guided Transit
The Automated Guided Transit systems have to run on segregated right of way.
Then we understand all the benefits of reduced geometrical size and very short
headways : a comparative analysis comparing the civil engineering costs depending on
the adopted transit systems allowed us to verify that the construction costs are linked
to the vehicles gauge of systems and that for an equivalent capacity, the civil
engineering costs (tunnel and underground stations with the cut and cover method at a
superficial level) of VAL 206 are lower by 8% to 17% than these of Light Rail for
7000 to 20000 phd. capacities, with 60 seconds headways for the VAL and 90
seconds for the LRT. For a deep tunnelling construction carried out with a Tunnel
Boring Machine (TBM), the differences of civil engineering costs of Val 206 and
Light Rail are between 17 to 31% less for the VAL 206 at 7000 to 20000 phd.
capacities. (Kühn F., 1992)
2.2 Site type and investment
From different implemented projects in France we find that civil engineering
costs ( not including the track) are in a range of prices such as shown in the
Histogram 2 below :
6F. Kühn
Histogram 2 : Civil engineering costs of VAL 206
Cost US $/km
Mix.traffic1
Mix.traffic2
Excl. RoW1
Excl. RoW2
Elevated1
Elevated2
Underground1
Underground2
0
5
10
15
20
25
30
35
40
45
Million US $
Type of RoW
Civil Engineering Costs of VAL 206 per km
Mix.traffi
c1
Mix.traffi
c2
Excl.
RoW1
Excl.
RoW2
El
e
v
ated
1
Source : (Kühn, 2001); valeur 2002 1 US $ = 1 Euro
2.3 Operation speeds
Automatic guided transit can be well-adapted to the track characteristics and
adopts a monitoring speed depending on the lengths of interstations, and acceleration-
deceleration (tyres vehicle) allowed by the motorisation of the vehicles. The stop times
in station are programmed, the dead time is suppressed, the high level commercial
speed, around 35 km/h in relation to a submitted conflicts transit system, is optimised
and respected. This high speed reduces the necessary number of vehicles to carry the
same amount of passengers at peak hour : thus, with a 35 km/h commercial speed we
must use a fleet of 34 Val 206 rolling stocks to carry 7000 phd. on a 10 km line; with
a 20 km/h commercial speed we must use a fleet of 51 Light Rail rolling stocks (TFS
type) that is to say 50% more.
2.4 Operating headway and service quality
The adopted headways on Lille's first line at the peak hour are between 72
seconds (60 seconds is a possible interval at the hyper peak -hour on the 1st line) and
3 to 6 minutes at off-peak hours and by night. This short headway allows a service
quality that cannot be offered by Light Rail subjected to traffic jams. The AGT has
also the regularity of a metronome, and a high degree of flexibility. We measure on
VAL's operation during 99.7 % of the time a running regularity at one second near.
Automation allows for substantial adaptability ; thus when there is a drift of peak hour
with abnormal crowding, a remote control signal from the central control room allows
the injection of several trains without the time needed to organise drivers, to oversee
the staff, to plan the operating schedule, etc. The operator adapts better to the users
demand, which brings to the transport user another service quality. (Frémaux D.,
1993).
7F. Kühn
2.5 Capacity
At the peak hour, with a minimum headway of 60 seconds the supply8 can be
of 9600 phd., and increases until 19200 phd. with a two-car train at a normal load and
26160 phd.(excep.load).
3. Comparison of 2 systems : the LRT and the AGT
3.1 Investment costs
From ten recent projects of LRT (111 km) in France the investment costs of
each system have been evaluated. The costs are in a range of prices such as shown in
the Histogram3 below:
Histogram 3 : LRT investment costs
Source : (Kühn, 2001), (Kühn, 2002); valeur 2002 1 US $ = 1 Euro
The cost range of "Civil Engineering and Appended Expenditures " can be
explained by the variations of the construction and on the workshop which is built
either for the line, or the future network or merely enlarged. The cost range of "Light
rail system" comes from the variation of the necessary supply, the fleet and the
electric power that must dispose the system .
As for VAL system, 5 lines under operation in France totalling 72 km allows us
to give the cost of civil engineering and the cost of the specific equipment linked to the
integral automated system control and the rolling stock. These costs are in a range of
prices such as shown in the Histogram 4 below:
8 At a normal load a VAL 206 car type carries around 160 pass.(4pass./m2) and 218 pass. (6 pass./m2) at
an exceptional load
Cost US $/km
Civ- Engin.1
Civ- Engin.2
LR System 1
LR System 2
Total 1
Total 2
0
5
10
15
20
25
30
M US $ per km
Expenditures
LRT investment costs
Civ- Engin.1
Civ- Engin.2
LR System 1
LR System 2
Total 1
Total 2
8F. Kühn
Histogram 4 : VAL investment costs
Source : (Kühn, 1997), (Kühn, 2001); valeur 2002 1 US $ = 1 Euro
The cost range of "Civil Engineering" comes from the percentage of
underground works : thus, 3 lines with 80% of their length in tunnel, one line with
90% of its length, at last one line with 40% of its length in tunnel.
The cost range of"Transit system" can be explained by the number of
trains/km operated on each line : thus, 2 lines operating 3.17 trains/km (Lille), 1 line
with 2.98 trains/km (Toulouse), 1 line with 1,7 trains/km (Rennes), at last 1 line with
1.11 train/km (Orly).
The Light Rail lines are designed to supply of around 2500 phd. with one-car
trains, the VAL's lines are designed to supply 9600 phd. with one unit trains.
The commercial speed of Light Rail is around 18 to 20 km/h in France while
the commercial speed of VAL is 32 to 35 km/h, this being principally due to the
necessary segregated right of way to operate an Automatic Guided Transit.
Definitively, these above costs show that on average among several lines :
- the equipment linked to the integral automated system control and the
rolling stock of an AGT as the VAL has a cost equal to double up to
triple that of the equipment linked to the Light rail system and its rolling
stock cost, for the first system the supply is 9600 phd. and for the
second the supply is around 2500 phd.
- the civil engineering has a cost for the VAL's system equal on average to
the double up to the triple that of LRT civil engineering cost. 40 to 90 %
tunnelling construction of a VAL line compared to only 10 % tunnelling
construction of LRT line.
Cost US $/km
Civ- Engin.1
Civ- Engin.2
Transit
System 1
Transit
System 2
Total 1
Total 2
0
10
20
30
40
50
60
70
80
M US $ per
km
Expenditures
Val investment costs
Civ- Engin.1
Civ- Engin.2
Transit System 1
Transit System 2
Total 1
Total 2
9F. Kühn
3.2 Operating Costs
From a comparative analysis of French Metros operating costs we take the
operation costs of Lille's metro for the year 1986 (after 2 full years of operation of the
first line 13.3 km long with 38 one unit trains), for the year 1988 (61 trains), for the
year 1990 (2 lines of 25.3 km long under operation with 83 trains), for the year 1995
(2 lines of 28.6 km long under operation with 83 trains) and for year 2000 (2 lines of
45 km under operation with 143 trains) the amount of supplied passenger places-km,
of annual trips with the corresponding costs for the year considered are represented in
the table 1 below in Francs & Dollars (without general and structural expenses, and
taxes).
Table 1 : VAL operating costs
LILLE’s VAL 1986 1988 1990 1995 2000
P.P.K. x 106643 681 1260 1396 2021
Trips x 10627 29 44 51 62
O & M Costs in
MF
in US M$
65
9.4
73
12.2
115
21.1
155
29.2
200
28.7
P.P.K. Cost in Francs
in US Cents
0.101
1.4
0.107
1.79
0.091
1.67
0.111
2
0.098
1.4
Trip Cost in Francs
in US Cents
2.40
34.7
2.51
42.2
2.61
48
3.04
57
3,22
46
Source : (Dtt, 1995), (Dtt, 1990). (Kühn, 1997) & (CUDL, 2001) Nota : P.P.K : Passenger Place-km. with 6
passengers/m2 - Average value of US$ :1 $ 86= 6.93 Francs; 1$ 88= 5.96 Francs; 1$ 90 = 5.45 Francs; 1 $
95= 5.30Francs ; 1$ 2001 = 7,80 Francs P.P.K : Passenger Place-km. with 6 passengers/m2
The operating costs of Nantes LRT are gathered for the years 1987 (1 line
10.6 km long with 20 trains), 1990 (after 2 full years of operation of the first line
12.6 km long with 28 trains), for1994 and for1998 (2 lines of 26.8 km with 46
trains), the amount of supplied passenger places-km, the amount of trips carried out
by year with corresponding costs (without general and structural expenses, and
taxes) are represented in the table 2 below in Francs and Dollars :
Table 2 : LRT operating costs
NANTES LR
T
1987 1990 1994 1998
P.P.K. x 106207 250 511 620
Trips x 10613.07 13.26 32,9 35,8
Operating Co
s
19.79 MF/3.29M
$
21.2 MF/3.88 M $ 67,2 MF/12,21M
$
86,1 MF/14,66 M $
P.P.K. cost 0.0956 F/1.59Cen
t
0.0848 F/1.55 Cents0.131 F/2,3 Cent
s
0,139 F / 2,36 Cent
s
Trip cost 1.51 F/24.8 Cents 1.59 F/29.3 Cents 2,04 F/37,1 Cents 2,40 F / 40,9 Cents
Source : (Semitan, 1987) et( Dtt, 1995) (Dtt, 1999).
Average value of US$ : 1 $87 = 6.01 Francs ;1 $90 = 5.45 Francs; 1 $94 = 5.50 Francs.
1$ 98 = 5,87 Francs
10 F. Kühn
Histogram 5 : VAL operating costs
Source : (Dtt, 1995), (Dtt, 1990). (Kühn, 1997) & (CUDL, 2001)
Histogram 6 : LRT operating costs
1987
1990
1994
1998
P.P.K. costx100
Trip costx 10
Operating costx
10M
0
5
10
15
20
25
Value in Francs
Year
Operating P.P.K. - Trip - Costs
P.P.K. costx100
Trip costx 10
Operating costx 10M
Source : (Semitan, 1987) et( Dtt, 1995) (Dtt, 1999).
If we compare the level of PPK costs, the PPK VAL cost is around 13 to 68%
lower than the PPK LRT cost; as for the VAL trip costs they are between 64 to 12%
0
5
1
1
2
2
3
3
V
alue in
Ye
Cos
Opera t ing- P.P.K.- Trip -
P.P .K. cost
Trip cost x 10
Oper at ing cost x
11 F. Kühn
higher than LRT trip costs.
On Lille's network, the productivity per employee was 15542 km.trains in 1986
and increased to 25306 km.trains in 1995 that is to say an increase of 63%.
On Nantes LRT network the productivity per employee is 10417 trains.km in
1987 and increased to 11149 trains.km in 1994 that is to say an increase of 7%.
For each of the 2 networks of urban transport (buses and metro), expenditures
and operation's fare income have evolved. The ratios fare income/expends
corresponding to the data of the whole networks (buses & metro) are lower than
fare income/expends ratios of the metros alone.
The « Separated Right of Way Transit » (TCSP9) influence » gives a certain
productivity of operation and an increasing ridership. Thus, in Nantes the fare
income/expends ratio of the Light Rail line in 1987 is of 115% when the ratio of the
whole network is 55%. In the same way in Lille, the fare income/expends ratio of the
VAL's first line is 111% on 1986 when the whole network ratio is 53%. In 1994, the
ratio fare income / expends for VAL alone was 100.5 %, in 2000 this ratio became
135 %.
Figure 1 : VAL’s network ridership betterave 1984 and 2000
Metro Patronage & Linear1984 -2000
0
10
20
30
40
50
60
70
1984
1988
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
year
million trips/ km
network
VAL Patronage
linear
Documentation : (CUDL, 2001)
9 TCSP : Transport en Commun en Site Propre
12 F. Kühn
Histogram 7 : Profitability of Metro’s network
Documentation : (CUDL, 2001)
Summing up, we can say :
- in Lille, the "metro influence" with the opening of 2 lines 25,3
km long stimulates the ridership which was low 51 millions trips with the urban
transport perimeter of 1 079493 inhabitants.
The ridership of metro’s network which was 21.1 millions in 1984 increased to 29,4
millions in 1988 with the opening of Line 1 bis, increased to 48 millions in 1998 and
55 millions in 1999 with the opening of 16 new stations and 62 millions of
passementiers. The whole network (Val + Tramway + Bus) carried in 2000 106.5
millions of passengers.
The ratio trips/capita /year is 97 in 2000 for an average ratio 126.5 in this range of
cities of more 300 000 inhabitants.
- in Nantes, the "modern tramway influence" with the opening
of 2 lines 26.8 km is less significant, the network's ridership before the opening of
light rail line was yet 51 millions trips with a urban transport perimeter of 505281
inhabitants.
The ridership of Tram’s network which was 7 millions riders in 1984 increased to
16.6 millions in 1992, to 26 millions in 1993 ( 21 km) , to 35.8 millions (27 km) in
1998.
This ridership was 83.6 millions trips for the whole network (Bus + Tram) in 1998.
The ratio trips/ capita/ year is 167 in 1998 for an average ratio of 135 in this range
of cities of more 300 000 inhabitants.
4. Technical evolutions of LRT and AGT systems
4. 1 Light Rail's évolutions
Evolution of the rolling stock
Light Rail Transit vehicles must be attractive, hence modern. The trend of the last
years is an increase in transport supply and productivity : vehicles are 20 to 40 m long
and 2.20 to 2.65 m wide with possibility of forming unit trains (1line in Guadalajara
0
50
100
150
200
250
300
Million Francs
19 9 4 2000
Year
1994 & 200 0 VAL Operating Budget
Ex pendi t ure
Re v e nue
13 F. Kühn
is designed to operate 5 unit trains 150m long); the unit capacity of these vehicles is
between 200 and 300 passengers.
The use of choppers with traction motors allows a progressive traction control
offering rolling comfort and a better use of adherence as well as consumption savings
during starting and at reduced speeds.
Asynchronous motors fed by inverters appear progressively, offering a
reduction of the expenses for maintenance of the motor, a reduction of weight and
volume of the motor, an increasing of maximum rotation speed and a reduction of
equipment.
Acceleration performances are required for increasing the commercial speeds,
so we assist to an increasing propulsion power : nowadays the power-to-weight ratio
is between 12 and 14 kw/ton.
The tendency of many networks in Europe is to adopt a low floor for their new
rolling stock. These networks adopt vehicles with low floors in order to facilitate their
access especially by handicapped persons, in order to improve exchange times at
stations and facilitate the insertion of platforms into urban space. Many networks
adopt low-floor LRVs which can be classified in three types:
- the intermediate Low-Floor unit added to existing rolling stock,
approximately 200 of this design are in use in Amsterdam,
Wurzburg,Darmstadt, Freiburg, Basel and Nantes networks,
- the partial Low-Floor between traction bogies, more than 1000 LRVs of
this design are in use in Grenoble, Paris, Rouen, St Etienne, Sheffield,
etc. networks,
- the 100 percent Low-Floor design, no steps inside, which is under
operation in the Bremen, Frankfurt, Strasbourg, Bruxelles, Bonn, Köln,
Munich, Zwickau, Braunschweig, Vienna networks. In all, more than
1000 all-low-floor vehicles have been delivered or ordered.
Operating methods and traffic control
Numerous networks have introduced aids to the operation of the tramway lines.
These aids can be classified into three categories :
- block system of the track by means of track loops and spacing signalling
on the line sections with exclusive right of way, especially in tunnels;
- priority at junctions with traffic lights.
- systems of supervision and areawide traffic control : setting up of a LRV
fleet management and Automatic Vehicle Location (AVL) system.
The potential of Light Rail Transit
A study made among 10 networks around the world, by TRL and INRETS
(Gardner, 1994), on the theme of the performance and potential of LRT in developing
cities shows that the observed maximum peak hourly flows were found in three
networks with a high percentage of separated right of way in Tunis (9330 phd),
Alexandria (El Ramel 13414 phd) and Manila (a 100% segregated right of way, on
viaduct : 19000 phd in 1994 and 28000 phd in 2001), the other 7 networks have an
average flow of 4500 phd at peak hours. So it is full segregation, an advanced
signalling system providing theoritical minimum headways of 85 secs. in Manila, 105
14 F. Kühn
secs. in Mexico (line A), 150 secs. in Guadalajara, and a number of vehicle well
adapted that can supply a high capacity .
4.2 Automatic Guided Transit's évolutions
The first lines under construction and operation of the VAL system (Lille 2
lines, Toulouse 2 lines, Orly one line, Rennes : 1 line) are characterised by the
following features :
- safety electronic equipments based on a "fail-safe" technology,
- fixed-block automatic protection system,
- platform protection by platform doors.
There has been however some evolution on the different points in the family of
mass transit systems, which will be briefly reviewed hereunder.
Use of microprocessors for safety functions
The Paris Metro Authority, RATP, decided to develop a new control system,
called Sacem, for its regional network, the RER, in order to enhance the capacity of the
lines ; this new system required the extinction of the wayside signals, and the use of a
cab-signal involving safe track-vehicles transmissions and a safe computation of the
stopping distances on board the trains. For the safety functions, RATP has promoted
the development of an architecture based on a single microprocessor protected by data
coding, called "vital coded monoprocessor".
This new architecture is now a standard for safety realisations in mass transit
systems in France (David Y., 1991), and has been already used on Paris Rer line A, on
Laon Poma, and on Lyons' Maggaly system, line 14 METEOR of Paris network, as
well as on the Chicago Airport's VAL line and line 8 (Urban metro) and line A (LRT)
of Mexico network.
Development of a moving block (ATP) system
Lyons' Authorities decided to adopt a moving block Automatic Train Protection
(ATP) for the 4th line of their metro network in order to obtain a better flexibility of
operation.
Platform doors
Since the opening of the first Val line in Lille in 1983, the use of platform doors
is considered in France as the most efficient way for preventing accidents. There are
used on the network of Toulouse, Orly, Rennes, and on the Météor line. In Lyon, the
Authority and the metro operator chose a conventional method based on a double
barrier of infrared beams, regularly spaced with 15 cm intervals, layed down above the
tracks.
Other technical evolutions
In complement to these three main innovations concerning the "system" aspect
of the lines under consideration, a number of other technical evolutions in the design
of the vehicles or of the ground equipments have been introduced, for instance, on
VAL line 2 of Lille network, the use of :
- electric vehicle doors instead of the pneumatic ones,
- GTO thyristors in the power control equipment,
15 F. Kühn
- optic fiber in ground transmissions,
- a new VAL vehicle called VAL 208 with the"wheel-motors", it means
one motor of synchronous type for each wheel of the vehicle instead of 2 DC
motors in each vehicle, with a traction chopper for each of them.
5. Conclusion
After an important decline in the fifties, LRT systems have recovered a certain
dynamism taking expression :
- in the creation of new networks ;
- in the improvement of existing networks ;
- in the improvement of rolling stock with extra low-floor light rail
vehicles ;
The main reason of this dynamism is that these systems can be operated at
grade on surface, they can be developed in stages. LRT is particularly well adapted to
a range of cities and conurbations with populations between 200,000 and 700,000
inhabitants, in which the construction of underground networks is hardly imaginable
because of the necessary investments.
AGT systems have a service quality, a flexibility, a regularity of metronome, a
safety that the LRT can reach in the same way with difficulty ; the main reason is
because AGT uses a fully automated driverless operation but it requires fully
exclusive right of way and stations, and with higher car and system costs, total AGT
construction cost is invariably higher than LRT construction cost. We saw in the
chapter 3 above "Comparison of 2 systems" that :
- From the investment point of view on average, the equipment linked to the
integral automated system control and the rolling stock of VAL has a cost
equal to double up to triple that of the equipment linked to LRT system
and its rolling stock cost, for the first system the supply is 9600 phd. and
for the second the supply is around 2500 phd. As for the civil
engineering and the added expenditures, they have a cost for the VAL's
system equal on average to the double up to triple that of LRT civil
engineering cost, the exclusive right of way generally obtained by a 80 to
90% tunnelling construction of a line, the LRT is satisfied with a
separated right of way on the surface with only 10% tunnelling
construction of their line.
- From the operating cost point of view
. in Lille, the "metro influence" with the opening of 2 lines 28.6 km long
stimulated the ridership, the passenger place-km cost which was 1.79 cents at the
opening of the second line decreased to 1.67 cents after two years of the 2 lines
operating in 1990 then 10 years after with 45 km of lines the P.P.K. cost
decrescendo to 1.4 cents. The productivity per employee was 15542 km.trains in
1986, it became 25306 km.trains in 1995.
. in Nantes, the "modern tramway influence" is less significant, with the
opening of 2 lines 22.8 km long stimulated the ridership which was 51 millions for
a served area of 464 857 inhabitants.The passenger place-km cost which was 1.59
cents in 1987, increased to 2.3 cents in 1994 and increased to 2.36 cents in 1998.
The productivity per employee was 10417 trains.km in 1987, it became 11149
16 F. Kühn
trains.km in 1994.
We think that to increase the productivity of investment costs, the VAL system
needs to operate in a high density area, not necessarily large city, and with important
vehicle fleets the operating costs will decrease, the productivity per employee going on
increasing with the opening of new lines of the network. With a large number of cars
to operate the AGT operating costs decrease in relation with the LRT operating costs
for a same supplied capacity.
When a city has a lack of land, generally in the centre, the future transit system
needs to be up-graded (in underground or on viaduct), the construction cost of the
system increases ; then there is a choice to do between an LRT or an AGT system
because the exclusive right of way is naturally necessary. An automatic guided transit
with its flexibility, service quality, safety could be implemented with an acceptable
overcost decreasing when the needed capacity grows.
At last, we think there is a need of the two systems for the cities, large or not :
- a high density city without land to give to surface public transport could
choose an AGT if the ridership to carry is sufficient, the service quality is
then high and the "image of metro" attracts the users of private cars,
- a middle size city which makes the choice to prohibit some roads to the
private cars, could then get separated right of way for a Light Rail and decides to
implement it : Light Rail schemes of the 1980s have shown that street operation with
predomently reserved running is both feasible and actually contributes to the
humanising of the city.
6. References
- Bigey M.& al., "Le tramway nantais", SEMITAN CID éditions, Nantes1986.
- David Y ., « Unmanned operation : economical evaluation and quality of service », in
proceedings of Urban Public Transport : a challenge for our cities, conference
organised by ENPC, mai 1988
- Frémaux D., "Automatisme contre automobile", dans Transport Public mai 1993.
- Gardner G., Rutter J., TRL Overseas Unit, Kühn F. INRETS-CRESTA (1993), ”The
performance and potential of Light Rail Transit in Developing Cities ”, Project Report
69 R5596, 25p, 1994.
- Kühn F, Martinet C. Semaly, « Etude comparative des coûts de génie civil selon les
systèmes de transport adoptés », INRETS-CRESTA Février 1992.
- Kühn F, « Light rail or Automatic Guided Transit », in processions of APM VI,
Creative Access for Major Activity Centers, édited by WilliamJ. Sproule, Edward S ;
Neumann, and Stanford W. Lynch, ASCE 1997, p46 – p55.
- Kühn F., « Emergence of intermediate urban transit systems », in proceedings of
CODATU VIII1998 Urban Transport Policy, Freeman & Jamet, 1998 Balkema, p381
to p390.
- Kühn F., « The VAL Lille Urban Community Metro’s Experience 1972 – 2001 »,
Presentation to KRRI, Seoul, 30 July 2001.
- Kühn F., « Bus rapid or light rail transit for intermediate cities ?, in proceedings of
CODATU X2002 Urban Mobility For All, Xavier Godard & Innocent Fatonzoun,
2002 Balkema, p357 to p365.
- Lesne J. ,"Panorama des systèmes de Transport collectif en site propre (TCSP), in
conférence organisée par le CEIFICI des 21 et 22 octobre 1992.
- Muller G., "Renaissance du Tramway", dans RGCF juin 1993.
- Yang Tzu-Pao, ENPC, « Bilan financier de l’automatisation intégrale des transports
collectifs urbains, thèse de doctorat du 7 novembre 1996.
ResearchGate has not been able to resolve any citations for this publication.
« Etude comparative des coûts de génie civil selon les systèmes de transport adoptés », INRETS-CRESTA Février 1992. -Kühn F, « Light rail or Automatic Guided Transit », in processions of APM VI, Creative Access for Major Activity Centers
  • F Kühn
  • C Martinet
  • Semaly
Kühn F, Martinet C. Semaly, « Etude comparative des coûts de génie civil selon les systèmes de transport adoptés », INRETS-CRESTA Février 1992. -Kühn F, « Light rail or Automatic Guided Transit », in processions of APM VI, Creative Access for Major Activity Centers, édited by WilliamJ. Sproule, Edward S ;
Balkema, p381 to p390. -Kühn F., « The VAL Lille Urban Community Metro's Experience 1972 -2001 », Presentation to KRRI, Seoul
  • F Kühn
Kühn F., « Emergence of intermediate urban transit systems », in proceedings of CODATU VIII1998 Urban Transport Policy, Freeman & Jamet, 1998 Balkema, p381 to p390. -Kühn F., « The VAL Lille Urban Community Metro's Experience 1972 -2001 », Presentation to KRRI, Seoul, 30 July 2001. -Kühn F., « Bus rapid or light rail transit for intermediate cities ?, in proceedings of CODATU X2002 Urban Mobility For All, Xavier Godard & Innocent Fatonzoun, 2002 Balkema, p357 to p365.
Panorama des systèmes de Transport collectif en site propre (TCSP)
  • J Lesne
Lesne J.,"Panorama des systèmes de Transport collectif en site propre (TCSP), in conférence organisée par le CEIFICI des 21 et 22 octobre 1992.
Renaissance du Tramway
  • G Muller
Muller G., "Renaissance du Tramway", dans RGCF juin 1993.