Sitting GCSEs is probably the most stressful experience that the average 16-year-old has to undergo.

What happens to their stress levels if the train taking them to the exam doesn't turn up - or arrives very late?

This is the experience that students and commuters across the north of England have been facing this week.

Dozens of trains have been cancelled, many of them at very short notice.

Many more services have been cut back or were running extremely late.

Routes between other northern towns such as Blackpool, Southport, Wigan and Manchester were heavily affected. But Cumbria hasn't escaped it. On Monday, 22 out of 36 services on the Lakes Line were cancelled.

Operators Northern put it down to a shortage of drivers.

New timetables were introduced on Monday and so teething problems were perhaps to be expected. But "teething problems" might be an understatement. Rail union the RMT have described it as "meltdown".

Many school pupils rely on the Lakes Line, and angry district councillors in South Lakeland are now arguing that Northern should be stripped of it.

The Government are promising action. Transport secretary Chris Grayling says tackling the problems is his "top priority", and Northern have submitted what they are calling a "timetable recovery plan".

Measures in the plan include improving driver rostering to get more trains running, increasing driver training on new routes to get more services on line as quickly as possible, additional contingency drivers and managers at some locations and extra peak services on some routes.

How long it will take to improve the situation - and whether it will help in Cumbria - remain to be seen.

Former Carlisle MP Eric Martlew has long taken an interest in the state of the railways.

When in parliament he founded the all-Party West Coast Mainline committee. To him, the problems of this week are symptomatic of those the trains have faced since they were sold to private operators - which he describes as "a disaster".

Northern Rail services, Mr Martlew says, have long been below par.

"The trains to Newcastle and west Cumbria are much too slow. But there are no plans to do anything about it."

It is not just Northern Rail services that leave something to be desired, he stresses. He believes the trains to and from London are also in decline.

In the first decade of this century the line between Euston station in London and Wigan was upgraded. But the stretch from Wigan to Glasgow - which passes through Oxenholme, Penrith and Carlisle - wasn't improved in the same way.

He says it shows. "The problems we are getting now are all between Glasgow and Wigan, because the infrastructure is starting to wear out.

"You get signal problems and lines coming down. It's a much less reliable service."

He sums up the situation as he sees it: "The West Coast Mainline is a modern line but it needs upgrading in its northern part.

"The Newcastle line and west Cumbria line are like something out of the early 20th century at best."

To him, the obvious answer is to renationalise them.

The East Coast Mainline, between Edinburgh and London King's Cross, has twice been taken back into public ownership after problems with its private owners.

When back in public hands the service improved, customer satisfaction levels rose and the line even made a profit.

Mr Martlew points out that a clear majority of the public - including most Conservative voters - now support rail renationalisation. And he argues that it could work out cheaper than the current set-up.

"We pay the private operators more in state money than we gave to British Rail. They take more and more subsidies every year.

"You can't have a national rail service run by half a dozen different companies. Other countries look at what we have done and say: 'We're not doing that.'"

He adds: "No matter what their political persuasion, most people support bringing the railways back under public ownership. But the politicians aren't going to admit that they got it wrong.They need to perform a U-turn."

However David Andrews, secretary of the Cumbrian Coast Rail Users' Group, is less critical.

He reckons that services in his area are fine - and are set to improve.

"There are some parts where the services are very poor, from Windermere to Oxenholme," he concedes. "There are all sorts of problems,

"But on the coast it's going very well."

Sunday train services between Whitehaven and Barrow are being reinstated after 42 years - opening up places like Millom to weekend visitors again. "It will be a big improvement in terms of tourism," Mr Andrews predicts.

He adds: "The last trains between Carlisle and Barrow are going to be about two hours later. Some of them look as good as new, with new carpets. And they're going to have wifi later on."

There also plans for a half-hourly service from Carlisle to Newcastle instead of the current hourly service.

"So there are good bits and bad bits," he says.

Rectifying the problems with the new timetable is not the only difficulty Northern bosses are facing this week. Yesterday and again tomorrow they've been hit by strike action by rail union RMT.

The rail company are doing away with guards on most trains but the union argues that they are necessary for dealing with incidents and accidents or stepping in when the driver is incapacitated - and so driver-only trains are unsafe.

"These strikes are not about wages or pensions or conditions," explains Craig Johnston, the union's regional organiser. "They're purely about safety and security. What else can we do?"

He's not surprised by this week's delays and cancellations. He blames them on poor management.

"Northern has long had a chronic shortage of drivers, and now it's ever more acute.

"They had this unrealistic expectation that everyone would do huge amounts of overtime, they were already short-staffed and now it's causing mayhem everywhere.

"They were calling Monday 'Meltdown Monday'. It was followed by Terrible Tuesday and Woeful Wednesday."