Rail workers picketed at Glasgow's Queen Street Station on Saturday
A 24-hour strike by rail workers in Scotland planned for next Monday is likely to go ahead after talks aimed at ending the dispute broke down.
Members of the RMT union are fighting plans to have drivers instead of guards operate the doors on a new rail link between Airdrie and Bathgate.
Operator First Scotrail said it was disappointed no agreement was reached.
Union leaders earlier expressed anger that a government agency has already backed staffing plans for the route.
It has emerged that Transport Scotland accepted First Scotrail's proposals for trains on the new Glasgow to Edinburgh via Airdrie and Bathgate service to be run with drivers and ticker examiners but no conductors.
The drivers would operate the train doors, a move the RMT has claimed could jeopardise passenger safety.
The union has also accused Transport Minister Stewart Stevenson of misleading it by not revealing that the transport agency had backed Scotrail's plans when he met with representatives for talks on the issue earlier this year.
The £300m Airdrie to Bathgate rail link is due to open in December.
About 550 rail workers took part in the first of three 24-hour walkouts at the weekend.
Following top-level talks between the two sides in the dispute, Pat Sikorski, assistant general secretary of the RMT, said: "It's ping pong and we want to know who we are to negotiate with, so we have asked for the full correspondence between First Scotrail and Transport Scotland.
"We have no plans for further meetings until we know who we have to negotiate with."
First Scotrail said it was "extremely disappointed that no progress was made".
Steve Montgomery, ScotRail's managing director, added: "The new line will create 130 new jobs - and the trains are safe. They are the same as those which have operated in Scotland for 25 years.
"It is difficult to understand why the union will strike, inconvenience our customers and possibly delay the reopening of the rail link which is funded by Scottish taxpayers.
"I would like to assure customers that should there be further strike action, we will do everything to keep services running as normally as possible."
Transport Scotland has confirmed that it has accepted First ScotRail's staffing plans for the new route.
A spokesman said: "Transport Scotland and the transport minister have been consistent and transparent in all dealings with the RMT.
"ScotRail recommended driver plus ticket examiner operation for Airdrie-Bathgate, and Transport Scotland received assurances that this was a safe approach for this route from the independent safety bodies the Office of Rail Regulation, the Railway Standards and Safety Branch and the Rail Accident and Investigation Board.
"The driver plus ticket examiner operation is already deployed across 56% of ScotRail journeys, which, as well as satisfying safety issues, is viewed as the most efficient way of offering long term value to taxpayers.
"The Scottish government accepted those recommendations on the basis that the terms and conditions of existing staff were protected and appropriate safety measures were in place."
As well as the strike planned for Monday, RMT members are also due to walkout on 13 March, the day of the Scotland v England RBS 6 Nations rugby game at Murrayfield.