C.F.D.'s Light Railcars

The term light railcar must be associated with a questioning of a number of 150-year-old constraints if it is to have any meaning. This means that new operating conditions must be considered for this equipment, and in particular the non-banking with conventional equipment. Otherwise, this notion of lightness must be replaced by the term "cheap railcar"

If, indeed, it is imperative to :

1° Keep the frame at the height of the standard buffer at 1 m 025 to undergo the compression tests of 150 tons to be incorporated into traditional equipment.

2° Weigh a minimum of 12/13 tons per axle to ensure shunting.

3° Use only railway components for which there is no possible competition on the market.

There are no more light railcars or cheap railcars, and SNCF can offer a wide choice of proven solutions from the unified 150 hp to the recent X 2100.

The requirements to talk about light railcar

Operation of existing track sections or reopening of certain lines.

• State of the track, average, with a minimum of maintenance so as not to penalise this mode of transport compared with road.
• Average passenger flow, but sufficiently regular over time to ensure normal filling of many daily services.
• Driving and operation by a single agent collecting the fare or controlling the ticket.

The different types of light railcars

• Type with two rigid axles. Wheelbase 7 to 10 m not very suitable for R curves less than 250 m.
• Two-bogie type for tight curves or mountain networks (e.g. WHITE-SILVER or CORSICA).

In the same way, the railcar can be intended to run alone or at most with a trailer or become a real "locomotive" and pull several trailers. Case of SNCF "all services" railcars or CORSE type X 5000 railcars (single or twin-engine).

The essential criteria to remember

• Economy of use
• Choice of minimum comfort, rather than that of speed
• Average capacity with the possibility of standing passengers in the event of occasional and unforeseen rush-hour traffic, such as city buses or metros.
• Multi-unit operation in case of permanent or expected traffic congestion.
• No toilet compartments, such as coaches or trams.

The presentation of a lightweight CFD solution

This problem had fascinated the Company in 1943 when railway operation was the Company's No. 1 activity (in 1940 it was operating nearly 2500 km of track with 3850 vehicles).

This is why, as early as 1945, five prototypes had been ordered from the BILLARD Company in Tours (See the technical data sheet for this equipment in Appendix No. 1).

On this occasion, Mr. ZENS, the Director of the CFD at the time, published in 1947 the article "Light railcars for normal track with little traffic".

Subsequently, the CFD workshops in Montmirail had to build ten similar machines of slightly increased power 120 hp PANHARD plus a number of trailers.

By 1968, when they were withdrawn from the Avallon-Autun line, these railcars had covered more than 8,000,000 km. It is interesting to note that the cost of these machines (hire- + major maintenance + minor maintenance) was lower than the maintenance cost of the 150 hp unified railcars alone.

We therefore believe that this type of railcar can be an excellent basis for a light railcar and in Appendix No. 3 we show what it could be if we were to build it in 1983.

The estimated cost of operating different solutions

Tables 1 and 2 give indications on the comparative cost of different CFD solutions, the main assumptions being the following:

• Average annual journey: 80,000 km/year
• Amortization over ten years
• Financial costs: 14 %/year.

In conclusion

The last part of Table 2 summarises the cost price for the space offered, and the choice can be based on this, taking into account the number of passengers to be carried.

source : L'autorail léger, Proceedings of the 1982 Exporail Symposium, by Gérard ROBERT