Currently, 3rd and 4th rail electrification is introduced in 1908, but the electrified tube stock first appears in 1890.
This is already fixed on the Github repository, but thank you for noticing!
I had already spotted that one myself but evidently I'd not changed it in SVN!
Sorry to gravedig this, but the problem persist in the latest nightly (r974).
Now it should be changed in SVN.