Rail workers are 'at breaking point' after bad weather brought chaos to the tracks and visitor numbers were up by 20 per cent due to the Edinburgh festivals, it was claimed.
The National Union of Rail, Maritime and Transport Workers (RMT) said staff were 'at breaking point' due to the pressures they were under.
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 cancelled yon Monday morning alone, as torrential rain again flooded Winchburgh Tunnel in West Lothian.
Services between Edinburgh Waverley and Glasgow Queen Street were reduced to a half-hourly service each way and at one point there was a speed restriction of 5mph going through the tunnel.
It is understood more than 150 Glasgow to Edinburgh services were cancelled when the tunnel was flooded on Thursday night and Friday.
Devices built-in which begin to pump water out automatically when it starts to build up were overrun due to the relentless rainfall, it was said.
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 [Winchburgh] 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.
"It is getting to the point that my guys are almost at breaking point."
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 the tunnel in 2015.
Specialist engineers are now 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 is also dealing with problems caused after miles of track became submerged or washed away near Inverness, Carrbridge, Ardlui, Crianlarich and Oban, bringing ScotRail travel disruption to and from the area.
The line will remain closed between Ardlui and Crianlarich until August 22 - leaving the prospect of more than 100 further services being hit.
Mr Hogg added: "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.
A Network Rail Scotland 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."