That might be the case on many commuter trains, but it’s a very different picture at other times of the day.
The Conservatives tried to make a big deal over their revelation that Edinburgh’s trams run only 25 per cent full.
But I dare say, the overall figure for ScotRail’s carriages will be even lower.
Outside the morning and evening peaks and away from the main inter-city lines, there is often plenty of space on board, while some trains run virtually empty.
This is the age-old problem for the railways - how to fill trains outside the rush hours.
It’s true that on major routes, such as the main Edinburgh-Glasgow line and those between the cities and Aberdeen and Inverness, space can always be at a premium.
That’s why ScotRail has ordered two extra fleets of trains, with the first due to start operating from September, and the second scheduled to go into service on longer-distance services from next year.
However, because there will be a net increase in ScotRail’s total fleet - fewer trains are being sent back down south than those arriving - that will mean even more seats to fill at off-peak times.
In fact, it’s been described as Scotland’s biggest rail expansion since Victorian times.
So it’s high time for a radical experiment - significantly cut fares.
This wouldn’t be across the board, as no one would want to make things worse again just as the rush-hour overcrowding was being eased.
Instead, ScotRail could use its new smartcards to offer vastly-reduced fares on trains it knew attract hardly any passengers.
These may be very early in the morning and late at night, and only on certain dates - obviously not during the Edinburgh Festival or during major events.
They could also cover Scotland’s rural lines during the winter, such as to Stranraer, Kyle of Lochalsh and Wick.
ScotRail has been set a target of replacing 60 per cent of paper tickets with smartcards within two years, and they will soon become the norm, with the ability to charge different fares at different times.
The operator will also be able to much more accurately gauge demand because many of its trains are to be fitted with sophisticated passenger-counting equipment to detect how full each carriage is.
So far, there have been only very limited cut-price fare offers, such as £5 singles on some longer routes.
Everyone loves a genuine bargain, so why not on the railways?
But it would have to be at a game-changer level for the car-driving hordes, who would need a very major incentive to try the train.
Offering next-to-nothing fares would both increase revenue by filling spare capacity and potentially introduce new passengers to rail, who might go on to become regular travellers.
Filling empty seats would provide more money for improvements, or reduce the massive amount of public subsidy the railways require.
The Scottish network costs more than £500 million a year to run, with the ScotRail train operating contract the Scottish Government’s largest.
If so much taxpayers’ money is allocated to the railways, they should benefit the very most people they can.