Scottish passengers would be among the first in the world to ride on battery-powered trains under plans unveiled by Japanese firm Hitachi.
The company wants to add batteries to the new electric trains it is building for ScotRail which are being introduced across the Central Belt.
It would extend the range of the Class 385 trains on to non-electrified sections of track.
That could bring the newer trains with their improved comfort to lines currently served by older and more polluting diesel trains.
Hitachi said the trains could run up to 60 miles on batteries.
It said recharging would take ten to 15 minutes.
That would mean the trains could run beyond Dunblane – the northern extent of ScotRail’s electrified network – as far as Perth and Dundee.
Hitachi has suggested other routes they could be used on including from Glasgow to East Kilbride and Kilmarnock, and on a Glasgow northern suburban line to Anniesland via Maryhill.
ScotRail has ordered 70 of the Class 385 trains, which will become its largest fleet.
Nearly half of them are in passenger service operating on routes such as the main Edinburgh-Glasgow line, and to Dunblane and Alloa.
Hitachi has been developing the technology for 15 years and built the world’s only passenger train running on batteries, in southern Japan.
The Dencha – dual energy charge train – has been operating since 2016.
A Hitachi spokesman told The Scotsman: “There are various options for the Class 385s, including installing batteries underneath.
“It would provide greater flexibility for the operator and save a huge amount in electrification costs.
“It would make ScotRail the first alternatively-fuelled passenger train operator in the UK.”
The plan follows Vivarail showcasing a converted London Underground train on the heritage Bo’ness and Kinneil Railway last October. Passengers were offered free trips on the five-mile line over several days. A short-lived battery train also ran on the Deeside line east of Aberdeen 60 years ago using a railcar known as Sputnik.
ScotRail said the Hitachi plan was “at a very early stage”.