6) ... That’s the system used here in the Southern Region of British Railways. This is the London to Newhaven boat train – the first boat train ever to be hauled by an electric locomotive in Britain. It’s an interesting locomotive. In order to maintain its pulling power over gaps in the conductor rail, it is fed by two generators which are kept going by a one-ton flywheel, which rotates throughout the journey. Even if the locomotive is brought to rest in the middle of a gap in the electric conductor rails, the flywheel has enough momentum to keep the generators running and so move the heaviest train out of the longest gap in the electrified system.

But I’m sure most of you already know quite a good deal about passenger trains. And yet carrying passengers is less than half the story. On the railways about 60 per cent of the revenue comes from carrying freight, parcels, newspapers and mails – and far the greater part of this 60 per cent comes from freight...