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Author Topic: Electrification of freight traffic  (Read 684 times)
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The future is 25000 Volts AC 750V DC has its place

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« Reply #15 on: Yesterday at 12:05:43 pm »

I think that the problem is in the specification of the class 92. 4MW off the third rail!

What might have been done is to provide emulator software like the class 91's (they can pretend to be any of the class 8X's!) so that they could substitute easily. If a 92 could pretend to be one or perhaps two 73's at most....

There's something called conductor line index, basically one unit per EE507 /185kW motor, so a 12 car unit = 12 (a REP consist = 14), a 73 = 8. The maximum allowed was 16 - a 92 powering would be over 32!

Perhaps there turned out to be too little freight to bother.


Basically yes.

There are areas in the Southern where double head 73 on third rail is not permitted.

The typical route setting (DC Protection setting) is for 4kA (3MW) High current railway can go to 6kA (4.5MW) the former Eurostar routes are high current railways.

High current railway needs to have 4kA rated circuit breakers with impedance protection the old falling voltage protection is not adequate, the track feeder cables need to be doubled to two 1000mm sq aluminium cables and the hook switches removed.  The rectifiers also need uprating to 3.5MW class G

There are still a lot of the older 2.5kA rated DC circuit breakers on the network these in the most part are ok at 4kA route setting

You can see why people think 25kV OLE is the future

Agreed, but there is still a limitation on the current draw through the OLE, 300A 7.5MW which is the typical rating, bare in mind OLE electrical section are much longer than DC so the number of trains in section become the limit

Neither a wise man nor a brave man lies down on the tracks of history to wait for the train of the future to run over him.     
Dwight D. Eisenhower
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« Reply #16 on: Yesterday at 06:30:12 pm »

As the channel tunnel only generated about 20% of the freight forecast, perhaps we should look to Southampton's 21 daily departures, many times that of Dollands Moor.

The idea of 25kV to Basingstoke was a very narrowly focused idea, neglecting the existing dc infrastructure. This dated firstly from the 1967 Pirbright Jn (a reasonable boundary for local trains) - Bournemouth dc scheme and was/is questionable for such a fast, long, high capacity line and has limitations in  powering services at its extremity. Wiring it would involve about c300km of track, 600M, and would also need to go North from Didcot.

Decarbonising freight means sorting out lots of other services.

Lateral thinking needed.


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