Hydrogen trains are being considered for north-east rail journeys in the future if studies show they should be supported.
The SNP Government unveiled its plans for rail carbon reduction last year, which includes the electrification of the east coast mainline between Aberdeen and Dundee by 2035.
However, hydrogen fuel cells over electric have been supported by recent research, prompting north-east MSP Tom Mason to raise the question in parliament whether a move to hydrogen-power is being considered instead.
Hydrogen trains are also due to be part of the COP26 climate summit which will be held in Glasgow this November.
Transport secretary Michael Matheson said that if hydrogen power is viewed as the most appropriate traction type for improving services, it will be taken forward.
Mr Mason quizzed the transport secretary over the consideration given to hydrogen power in the future and asked whether it will be put on hold for the Aberdeen to Dundee line until after full electrification is achieved – by 2035.
He said: “The first hydrogen trains are due to be displayed at COP26 later this year, demonstrating the future of sustainable rail travel.
“My concern is that the mainline to Aberdeen is only due to be electrified by 2035. In addition, electrified gantries are visually unattractive, expensive and in any event half the energy is lost in transmission.
“It is possible hydrogen trains could be introduced on the line at a reduced cost to electrification and very much sooner.
“I am worried we could face a situation where electrification is finished only for the line to face more long-term disruption to introduce hydrogen technology.”
Mr Matheson highlighted a project at Bo’ness and Kinneil railway, where a former ScotRail engine is being rebuilt as a production-ready hydrogen train in his answer.
He replied: “Scotland is one of the leading countries in taking forward hydrogen in the use of rail services which is why we have the present project taken forward at Bo’ness.
“The member can be assured that it is one of the areas that we are looking at, and if it is viewed as being the most appropriate traction type for improving services in the future to Aberdeen, then it will be the approach will be taken.
“But that analysis is still being taken forward and electrification and battery electric trains are also being considered that this time.”
The Bo’ness train will be demonstrated at COP26 and is also planned to serve as a development platform for technology providers and academics.