Rolling Stock Retirement Sequence, Which Should Go First

[schmod]

Why on earth are there so many NiCD batteries on each car?

Seems like it would have been much less of a headache to use plain old automotive batteries, or switch to a more modern battery chemistry as time went on...

[dcmike]

The batteries are needed to provide power for the car when it goes through railgaps or the DC converter fails. They also are used to power critical systems like lighting and radios during emergencies such as traction power (third rail) failures.

NiCd is actually the more modern and preferred battery composition for this application. In fact, that's what the 7000 series cars use. "Car batteries", or lead-acid type, were what the older cars were originally delivered with.