Batteries or fuel cells in trains are dumb, just build the damn catenary line or 3rd rail to supply the power, it will be expensive short term but MUCH CHEAPER in the long run.
Background: In Wegberg-Wildenrath, Notebookcheck.com was able to take a look at (and take lots of pictures of) the latest electric multiple units (EMUs) with LTO (lithium titanate oxide) batteries and fuel cells, which can run independently of an overhead line (electrical cable). We also show the first large fleet scenario that will take place around Berlin.