IF you think it is harder to get a seat on your morning commute than it used to be, you are not imagining things.

While ScotRail's passenger volumes have surged to an all-time high over the past decade, the growth in capacity has lagged far behind - with only one extra seat for every 3,300 additional passenger journeys.

The shortage of rolling stock has been highlighted most recently by the launch of the new Borders Railway, which has been quickly became a victim of its own success as passengers complained about being crammed into two-carriage trains and ScotRail battled increase capacity by borrowing carriages from other routes.

On Thursday, overcrowding forced the cancellation of two Borders Railway services.

The situation hints at a much wider problem for Scotland's rail operator, however, with figures obtained by the Herald revealing that passenger volumes have grown more than three times faster than capacity.

The Herald:

While annual passenger journeys on ScotRail have surged 35 per cent over the past decade - from 68.7 million in 2004/5 to a record-breaking 92.7m last year - the total passenger seating and standing capacity of the trains has increased by less than 10 per cent, from around 63,000 to 69,000.

If every available carriage was used, there would be around 53,000 seats compared to 45,979 seats in 2004 - a 15 per cent increase over ten years.

The figures exclude Caledonian Sleeper stock, which has been hived off into a separate franchise run by Serco.

Transport consultant, David Spaven, said: "I guess a lot of rail travellers will recognise the fact that too many trains are crowded these days, but from the point of view of railway economics - railways make more sense when you're carrying lots of people because you keep the unit costs down.

"It's horrendously expensive to run trains when they're half empty, so part of what we're seeing now is a success story in the sense that more seats on trains are now being occupied by people as opposed to fresh air.

The Herald:

"But then again, you don't want to have situation where many people are travelling in an overcrowded situation, so it's partly down to how you deploy and prioritise the rolling stock you have."

Since privatisation, the former British Rail fleet has been carved up between the three major rolling stock companies (Roscos) - Porterbrook, Angel Trains and Eversholt - which lease carriages back to the operators.

The arrangement costs ScotRail around £86 million annually.

Last month RMT accused the Roscos - all ultimately owned by overseas investment funds as far afield as Australia and Hong Kong - of "gross profiteering" as figures revealed they had made billions of pounds in profits while overcrowding on British trains increased.

Ken Sutherland, spokesman for Railfuture Scotland, said passengers were suffering from a "legacy of neglect".

He added: "The availability of rolling stock can be touch and go. For example, the train which crashed into a stolen car this week is going to be out of service for several days at least so that will have a knock-on effect for capacity.

"The availability of rolling stock in stretched to its absolute limits."

The Herald:

By December 2019, Transport Scotland expects to have 324 trains in the ScotRail fleet, compared to 287 now. Outdated stock will be replaced by 70 brand new Hitachi trains from 2017.

A spokesman said: "The Scottish Government is investing a record £5 billion in our railways to 2019 to improve rolling stock, rail infrastructure, all of which will ensure that Scotland’s rail network remains among the best in the UK.

“Within the investment in the Scottish rail network over the coming years there will be significant investment in new and refurbished trains.”