It is one of Scotland’s most scenic railway lines, taking in the Grampian Mountains, Cairngorms National Park, Blair Castle and some of the country’s most picturesque lochs and rivers.

The Highland Main Line began life as a modest route from Inverness to Nairn, but by 1863 it had surmounted both Dava Moor and the summit of Druimuachdar, the highest peak on a British main line at 1,484ft.

It now runs for 118 miles, linking a series of small Highland towns between Perth in the South and Inverness in the North and takes in some of Scotland’s best tourist attractions.

Many of the Stations are unique listed buildings and the line itself is testament to a magnificent feat of Victorian engineering over a challenging terrain of high mountains and rivers.

Passengers on the line can visit historic sites at Badenoch and Strathspey, as well as attractions including the Beatrix Potter Centre and Pitlochry Festival Theatre - and it is now hoped the route will draw even more visitors to the country as part of a sustainable tourism campaign.

The Highland Main Line Community Rail Partnership - set up in 2015 to oversee the care of the railway, and its stations and attractions - is set to join rail partnerships from across the UK taking part in Community Rail in the City.

The campaign will see the local groups visit large city centre stations on Wednesday to promote rail tourism.

Representatives from Highland Main Line Community Rail Partnership will take a little bit of the Highlands to London’s King’s Cross station to tell commuters about the attractions on offer along the route.

The campaign will also encourage more people to consider the environmental benefits of travelling by rail.

Sally Spaven, from Highland Main Line Community Rail Partnership, said the campaign offered the chance to promote Scottish tourism in a more sustainable way.

“Community Rail in the City is a great opportunity for us to promote our wonderful railway line to thousands of commuters and potential visitors,” she said.

“We know very well that Highland Perthshire and the Cairngorms National Park has so much to offer domestic and foreign visitors, from the Beatrix Potter Centre, Blair Castle, Pitlochry Festival Theatre, Highland Folk Museum, Cairngorms Reindeer Centre and many historic sites in Badenoch and Strathspey.

“In particular we suggest that it is a great area to visit for the stunning scenery, heritage and wildlife.

“We hope that Community Rail in the City will help us get that across to wider audiences and encourage people to visit by rail rather than car.

“As well as being a more relaxing and pleasurable way to travel, visiting the Highlands by rail benefits the local economy, and means less traffic, noise and pollution in our communities.”

The Highland Main Line was the brainchild of engineer Joseph Mitchell who had in-depth knowledge of the terrain - because he had walked across all of it.

The route was constructed in just 23 months and completed on September 9, 1863. Just six days later Queen Victoria travelled on the new railway to Blair Atholl to visit the Duke of Atholl at Blair Castle.

Highland Main Line CRP will be at King’s Cross from 7am to 7pm on Wednesday and will be accompanied by the Atholl Highlanders, the only private army in the UK and the cast of “Summer Holiday”from Pitlochry Festival Theatre.

A total of 39 rail partnerships will take part in Community Rail in the City, organised by the Association of Community Rail Partnerships (ACRP), including Tyne Valley who will be at Glasgow Central Station promoting their line.

Jools Townsend, chief executive of the ACRP, said commuters at the stations will be offered information on day trips and holidays by rail.

He said: “We’re really pleased that Highland Main Line CRP are getting involved in this important national campaign to promote exploration of their historic and scenic local railway lines.

“Across Britain, community railway lines take you off the beaten track, to some of our most amazing and fascinating destinations – and travel on them is especially rewarding, as they played a crucial part in our heritage, and bring you right into the heart of communities.

“Today, our members will be popping up at stations across Britain and engaging thousands of commuters to inspire and advise on daytrips, weekends and holidays by rail.

“This sort of tourism by rail is great for the families and holiday-makers, it’s more sustainable than driving, and it provides a critical boost to local economies.”