Batteries in all powered stock?

[JKF]

Will there come a point in future when battery tech has improved (in terms of output per size/weight) such that it becomes worthwhile having low-range batteries in every bit of powered rolling stock? The benefits of this would be that there would be less requirement to wire up depots, little-used crossovers and such, which has safety benefits as well as potential cost savings (balanced against cost of battery tech and cost of transporting the same). This would also be of benefit to stranded trains when power is shut off. Batteries would be charged during normal operation or from shore supply in depots if required.

what would be other advantages or pitfalls? I’m thinking of something with very short range so that it won’t take up too much space - maybe capacity to move a couple of miles at low speed.

 

[Bald Rick]

There already are batteries in all powered stock, they just aren’t connected to the traction system (and not big enough).

But I think, yes, it is likely that this could happen for electric trains - useful for depots and also as a ‘limp mode’ to get to the next station in the event of a power failure of any nature (straight failure, ice / flooding of conrail, falling off the wire / losing the pantograph, etc).

A 50kWH battery pack would provide a typical 4 car unit about 5-10 miles in limp mode. It would weigh less than half a tonne and cost about £50k if installed new or on refurb as part of a large scale programme.

 

[Bletchleyite]

If you mean "donkey batteries" for moving around depots and emergency low speed recovery, it's already happening - the Merseyrail 777s have them. Yes, I think it will become common. Much safer, as you say, if you don't have 25kV knocking around the depot or workshop (or even more so third-rail), and no need to shunt things in and out.