Yep, but you're suggesting that a train which with a diesel motor that weighs that much, wouldn't be an issue with batteries. If you are going electric, skip the batteries and go over head tram lines and be done with it.
Range. Plain and simple. It takes 10-15mins to refuel a train, you're not recharging a massive bank of batteries in 10-15 mins. On top of that, colder areas mean even less range.