RAIL staff are "almost at breaking point" while trying to deal with the extra pressure of providing 'the best railway Scotland has ever had' as extreme weather keeps major parts of the network at a standstill.

That's the view of the National Union of Rail, Maritime and Transport Workers (RMT) which said they are already concerned there was not additional staff to deal with a 20% increase in trains as visitors flock to Scotland for the Edinburgh Festival before the torrential rain hits Scotland.

The RMT concerns have come as hundreds of train services on the Glasgow to Edinburgh line and the world-famous West Highland Line were estimated to have been cancelled over the past week as engineers continue to deal with flooding issues.

More than 50 Glasgow to Edinburgh services were estimated to have been cancelled on Monday morning alone, as torrential rail again flooded Winchburgh Tunnel in West Lothian.

Services between Edinburgh Waverley and Glasgow Queen St were reduced to a half hourly service each way and at one point there was a speed restriction of 5mph going through the tunnel on Monday morning.

READ MORE: Commuters hit as floods shut down Glasgow to Edinburgh rail services

It is understood more than 150 Glasgow to Edinburgh services were cancelled when the tunnel was flooded on Thursday night and Friday.

The continuing issues come despite Network Rail Scotland, which is responsible for the infrastructure of the rail network, renewing the track, and drainage systems, through Winchburgh tunnel in 2015 and there are pumps built in which begin to pump water out automatically when it starts to build up.

They have specialist engineers examining what additional measures could be put in place to further improve drainage at the location.

Meanwhile it is estimated that more than 120 West Highland Line services, including the daily Caledonian Sleeper services to Fort William, have been disrupted in the eight days since a section was shut last week after it partially collapsed.

Sleeper services now start at Edinburgh Waverley and northbound services terminate at Dundee. Alternative road transport is being provided to connect both locations with Fort William.

Network Rail Scotland, which is responsible for the infrastructure of the rail network, has dealing with problems caused after miles of track which became submerged or washed away near Inverness, Carrbridge, Ardlui, Crianlarich and Oban, bringing ScotRail travel disruption to and from the area.

Last Tuesday night it emerged that 10 metres of the world famous West Highland Line have been swept away and there had been warnings the section between Ardlui and Crianlarich and between Crianlarich and Oban would be shut till Monday.

But now it has emerged that the line will instead remain closed between Ardlui and Crianlarich until August 22. - leaving the prospect of more than 100 further services being hit.

RMT Scotland organiser Mick Hogg said: "It is very difficult to deal with because the staff are under extreme pressure to deliver the train service, particularly with the bad weather we have had. It is a nightmare due to the flooding at the tunnel.

"But we would normally at the Edinburgh Festival, have additional staff in order to help and assist colleagues that are there, but we have none to deal with the festival activity.

"And that has a detrimental effect on existing staff.

"My members are under extreme pressure to deliver constantly particularly with an additional 20% increase in trains over the festival period with no extra colleagues to help and assist.

"It is getting to the point that my guys are almost at breaking point."

The latest rail headaches caused by extreme weather, come after hundreds of services were cancelled or delayed on Scotland's railways over four months since the launch of a winter timetable on December 9 was due to ScotRail staff shortages, and the train operator has previously said that is partly because many have been undergoing training.

ScotRail then said that was partly caused by the late arrival of the new Hitachi Class 385 and high-speed InterCity trains.

READ MORE: Disruption as flood-hit West Highland Line wont re-open for two weeks

The train operator had said its new electric and high-speed trains including the environmentally friendly Hitachi Class 385 stock would allow shorter journey times, more seats and more services on updated routes to build "the best railway Scotland has ever had".

Mr Hogg added: "Don't forget what the ScotRail and politicians are advocating is 'the best railway Scotland has every had' but it is an absolute shambles.

"We need to have a train service that puts passengers first.

"All ScotRail seem to be interested in is running the trains, they are not taking into account the morale of staff and the fact they are under extreme pressure in order to deliver. It's ridiculous."

READ MORE: Row over ten day closure of Harry Potter-featured West Highland Line

A Network Rail spokesman said: “We are sorry for the inconvenience this incident has caused our customers. We invest millions of pounds every year in projects to improve drainage and prevent flooding on Scotland’s Railway."

A ScotRail spokesman said: “We are continuing our recruitment of frontline people to help us make Scotland’s Railway better, and since 2015 we have 13 per cent more people employed within the business.

“The investment in drivers, conductors and our other customer-facing roles is helping us to deliver the service our customers expect and deserve."