I recently bought a box of bricks and was able to put together the 131 Passenger Coach from 1972… this was dangerous as I actually have parts from the 7722 Steam Cargo Train (1985) in my old LEGO pile.
After getting batteries, I nervously tried the engine and for the first time in this millennia, the train was running again!
Unfortunately, one curve track and one straight track were both broken. The curved one fortunately has a clean break so fit neatly together. The straight one was worse of.
I had a single blue straight track and to my delight it was same length.
Alas, to my dismay it does not have the special connection needed to connect to the tracks.
But that was easily solved with some normal lego plates and off we go!