SOLVED. Sci-fi city on wheels runs on rails... [s]

[Roger]

City that runs on rails, the inhabitants must move the rails from behind to before or catastrophe will befall the city. Scouts explore the forward terrain but the further they get from the city the more odd the city world view appears

[Sue]

Perhaps Inverted World by Christopher Priest?

[Lobstergirl, au gratin]

I second Inverted World. Actually they're exploring the terrain behind them (I think) and they find out they get shorter the farther they walk, because the gravitational forces are increasing. That's the reason the city has to more forward, to escape being crushed by gravity.

[Roger]

I reckon you've nailed it... thanks. Seems to me that it is an allegory for people belonging or brought up in a cult or religion that begin to discover the world is not entirely like their teachers have described it. The more they are exposed to the world beyond the cult the more they understand what has been done to them. The cult leaders, in this case, are as in the dark as anyone else. Maybe like the western enlightenment emerging from the theocratic catholic rule of the Middle Ages.

[Justanotherbiblophile]

Another interesting 'lay the rails so we can move the train' is Iron Council