Four years after it was taken out of service, this green machine should soon be pulling scheduled passenger trains again.

The diesel locomotive that has been plagued by technical problems ever since it was purchased in 2013 appears to have been fixed at last.

No.21 is undergoing tests after repairs to its undercarriage were completed. It was taken out of traffic in June 2015. Some £246,800 has been spent on fixing the loco, on top of its £420,000 purchase price.

On Tuesday this week it was used to pull an empty dining train to Port Erin and back.

A spokesman said: ’The loco continues to be available for use and the testing has been going well. We have completed a number of enhancements to the control systems and continue to complete our test regime on the loco during a busy rail season.

’We also need to undertake additional driver training, however, we remain on course for bringing the loco into service shortly and hope maybe even do some services in the next few weeks.’

Unkindly dubbed The Cabbage, no.21 was due to be named Vignoles - after influential British railway engineer Charles Blacker Vignoles.