Strangely, as, I although I have always been interested in trains, the sort of mechanical detail described above fascinated me at the same time as going over the top of my head. But I did read it all, with interest.
But I searched in vain for the answer to one question that occurs to me. Bearing in mind the enormous loads of a train, as opposed to a lorry for instance, how did they apparently overcome the grip required by steel on steel. As a trainspotter as a lad a regular featuire of watching a steam engine start from stationary was the overpowering of the engine causing several rapid spins of the driver wheels.
I didn’t see or hear the same with the diesels, so how come? 
And also, how have they done the same with electric? 
