I should have realized how fascinated my Dad was with trains at an early age, but somehow I didn't.
When I was tiny - just four years old - he would ask kindly engine drivers at Liverpool Street station to show me round the cabs of their giant steam engines - Britannia and others - that pulled the express trains that would roar through our local station. The vast expanse - as it seemed to a small boy - and the roaring heat of the firebox are impressions I've never forgotten.
Or he'd take me to a nearby bridge to watch the trains go by. He bought me my first trainset when I was five. It was clockwork, with an oval of O-gauge track and two tinplate carriages. It just went round and round but I loved it. I moved up to an electric train - Triang OO gauge - on my seventh birthday. It was a success, because I have loved everything to do with trains ever since.
But I never realized how deep his own interest was until much later. After he retired my Dad would often call phone-in radio programmes, and it was to one of those that he told his own childhood railway story. Money was scarce back then, and toy trains were expensive even for the people who had money. He would have loved one but it was unimaginable. But one Christmas he got as a present a toy railway signal. Just the signal, nothing else - no track, no trains, just the signal.
Signals then were more than just lights. They had a long red arm which moved up and down, its position telling the train driver whether he could proceed or not. Down and horizontal, it meant stop. Up at an angle, meant go. At night, red and green lights shone through colored glass. It was operated by a signalman, in a signal box possibly a long way off. It was his sheer muscle power, transmitted via up to a mile of thick steel cable, that made it move.
For my Dad, the rest of the railway lay just in his imagination. A train was coming, the signal must be pulled to show clear. The train rushes by in a cloud of steam and smoke, the noise deafening, loaded goods wagons banging and bouncing over the joints in the track. Then it has gone leaving only a cloud of dust. The signal must be set to danger behind the train. But wait, there's another one coming, a passenger train, the express. The gleaming engine rushes past, passenger's faces peer out of the varnished carriages. Again the signal must be pulled off, the signalman putting all his weight behind the lever as the heavy arm rises.
But all this was only in his imagination. In reality there was just a small boy and a toy signal, as he moved the arm up and down.
After he had told his story on the radio, other people called in to say he'd reduced them to tears.