I was traveling west along a highway in Iowa, two lanes that paralleled a railroad. This big old train pulled up along side. For some damn reason I got it into my head to race ahead of the engine so I could stop and get a picture of it going by. Well, the faster I went the faster it went. I’m doing 80 or more thinking I’m gaining only to see it just behind in the mirror. This went on for a long time and I had to scoot through a few towns and then speed out on the straights - I just could not get ahead. After awhile I thought I noticed I had gained distance. I came to a narrow S-turn overpass that crossed the railroad and pulled over to the right as far as I could. It was a very dangerous place to stop. Semi rigs would climb the bend and the whole thing would shake.  Well, I didn’t realize the train had been slowing down and I waited -dodging traffic - as the train came on slower and slower coming to a dead stop 50’ feet from my shaking bridge...... I was delighted.