The business case to reinstate the Douglas Bay Horse Tramway along the full length of the promenade has put the cost at ‘less than £2m’, the heritage railways’ chief engineer has revealed.

In an interview with Manx Radio, Andy Cowie said work to return the track to the Sea Terminal could begin in September and take around 40 weeks to complete.

The Department of Infrastructure submitted a business case to Treasury but has since been asked to make amendments and return with a revised proposal.

The original estimated cost of the extension was £750,000, but Mr Cowie said prices had risen significantly since then.

He told the radio station: ‘The figure in the business case was less than £2m.

‘To put that in context, the original cost was about £750,000, but the world has moved on significantly since the Prom project was planned.

‘Costs have gone up substantially in a number of areas, particularly steel, concrete and labour.

‘We also have to do a little bit more work because the surface has been laid. We now have to take that back up again, which obviously adds an extra cost.’

Horse trams last ran to the Sea Terminal in 2018 before services were suspended during the £26m Douglas Promenade reconstruction scheme.

Services resumed in 2022 on a shortened route operating only between Derby Castle and Broadway.

Plans to restore the line to the Sea Terminal were paused in 2021 after funding was reallocated - a decision that has continued to attract criticism.

Mr Cowie said Treasury had reviewed the business case in detail and returned with some ‘sensible comments and suggestions for us to look at’.

He said the revisions required were ‘relatively quick’ and he hoped they would provide Treasury with enough reassurance to recommend the business case before it is presented to Tynwald for a final decision.

Mr Cowie said work on the extension was unlikely to begin before September because of the lead-in time required to obtain specialist track of the correct gauge.

He said laying the 1.8km of track, including several sets of points and control mechanisms, could take up to 40 weeks, although he stressed that was ‘very much a worst-case timeline’.

Mr Cowie said it was ‘far from ideal’ that the tramway currently only operated along half its original route and restoring the line to the Sea Terminal would ‘open up quite a number of different markets’.

Passenger numbers rose to 55,000 journeys last year, an increase of 10% on the previous year.

Mr Cowie said: ‘Completing that track will open up [demand from] cruise ship visitors, which was probably our major driver, and that will increase passenger numbers significantly and provide a much better experience for our cruise ship passengers.’

The Department of Infrastructure said: ‘The DoI has been asked to review a recent proposal to the Treasury and return with a revised business case. An update will be provided in due course.’