Yeah it does. There's limited capacity on the rail network, right? In most cases, it's at capacity so they can't put on any more trains. So there's only so many people that can travel, but MORE people than that actually want to. So the only option is to raise the prices until enough people are put off that demand is equal to supply.
When I commuted in Manchester, the return ticket in the morning was something like £4.60, and a return bought in the evening (ie going to the pub in town) was 60p! Lots of people want to travel in rush hour, so demand is high, but in the evening the trains are empty so prices are lowered to stimulate demand.