NEW Rail Minister Jo Johnson’s pledge to ban diesel trains is more “jam tomorrow,” transport union RMT charged today.

Mr Johnson said the government would “aspire” to phase out “diesel-only” locomotives and multiple units by 2040 — despite the Tories having scrapped electrification plans last year.

Mr Johnson said: “I would like to see us take all diesel-only trains off the track by 2040.

“If that seems like an ambitious goal, it should be and I make no apology for that.”

Only last summer, Transport Secretary Chris Grayling cancelled plans to electrify rail lines in Wales, the Midlands and the Lake District.

Instead, the Tories have championed “bi-mode” trains which can switch from electric to diesel tracks.

Mr Johnson said such bi-mode trains were a “good bridging technology” to a future of battery and hydrogen power.

But the RMT said the minister had included “the most glaring contradictions” in his speech, which he delivered at the British Museum in London.

“If you were serious about cracking on with the phasing out of diesel trains you wouldn’t be scrapping key electrification projects, which will mean the commissioning of more diesel-operated fleet,” said general secretary Mick Cash.

“Instead of promises of jam tomorrow we need to tackle the crisis on Britain’s railways today and that means a planned service, publicly owned and free from the exploitation that has left the British passenger paying the highest fares in Europe.”

Mr Johnson suggested there would be public money for developing new technology, but Mr Cash said there should be “no free ride” for the private sector.

A source at drivers’ union Aslef branded the plan “all blow and no go.”

And the Institute of Mechanical Engineers noted that bi-mode trains “emit even more emissions than diesel trains” due to the weight of their equipment.