A union and a rail operator are to begin talks in a long-running dispute over driver-only operated trains.
The RMT has held strikes on Merseyrail over the issue, which the union believes risks passenger safety.
The talks, which will begin on Thursday, come after the rail operator wrote to the union to say it would enter them "accepting the outcome may be a second person on every train".
Merseyrail said all options "will be considered" to end the dispute.
The rail operator, which wants to introduce driver-only operated trains from 2020, has said the system is safe and is already widely used on networks such as Greater Manchester's Metrolink and the London Underground.
RMT general secretary Mick Cash said Merseyrail's "previous refusal" to consider a second person on board had been a "blocking point" for any talks taking place.
He said the union would now "seek to examine all possibilities of how the parties can bring about the realisation of the option".
Merseyrail's Jane English said all options will be considered to "achieve a resolution" at the talks, which are being chaired by arbitration service Acas.
"It's early days in the process but I am pleased the RMT has taken this first step in endorsing independent conciliation as a means to getting an end to this dispute," she said.