In the Pre-Budget Report, chancellor Alistair Darling put a lot of emphasis on the environment and used that for part of the stimulus package. He claimed £535m would go into bringing forward a plan to build more trains as well as put more efficient heating into low-income homes.
Darling claimed £300m would provide 200 new trains and it says that in the written version of the speech as well. But a closer inspection of the written report (p8, 112, 125) reveals that the money is for "up to 200 new rail carriages [to] be delivered earlier". Not quite 200 new trains then. More like 25.
At the same time, about £400m of spending is being brought forward to put more lanes on motorways.