Carillion is the main contractor on the project and has started early works on the line.

The project, which enables trams to run on existing rail tracks between Sheffield and Rotherham, was scheduled to finish in 2017 but Network Rail said it no longer expects to meet that date.

A “thorough review” has now been ordered into the project, with a new launch date expected later this summer.

This is the latest in a long list of delays to the project since it launched in 2012.

It was initially scheduled to open by the end of 2015 but was delayed until spring 2016 while Network Rail tried to obtain planning permission from the Department for Transport.

The completion date was pushed back again last October to 2017 because of further planning issues.

A Network Rail spokesman said the project team was carrying out a thorough review of the programme.

It is expected to report back to stakeholders in the summer.

The spokesman added: “As we develop this new technology, we are committed to sharing our learnings with the industry in order to aid the efficient implementation of tram train schemes elsewhere in the country.”

However the delays have been met with frustration by local stakeholders.

A South Yorkshire Passenger Transport Executive spokesman said: “We acknowledge that the design, planning and construction to allow the vehicles to run on the heavy rail network is complex.

“However, we are extremely disappointed in this news. All parties remain committed to the delivery of the project and to starting tram train services at the earliest possible time.”

Carillion has been contacted for comment.