From 1917, the Royal Navy train ran daily between London Euston and Thurso during both world wars. It was named after Admiral Sir John Jellicoe and carried service personnel to and from Naval bases around the country, including Scapa Flow. WW100 Scotland reports that in WW1 it ran 15 February 1917 - 30 April 1919.

It was estimated to have transported some half a million Service personnel during the two wars. (Helmsdale says half a million in each war). It was the longest scheduled rail service ever to run in the UK^▸ (United Kingdom).

Crewe Station was one of the few scheduled stops on the 717-mile 21h 30m journey. This was a major refreshment stop, where over 300 women volunteers worked around the clock to provide refreshments in a canteen on Platform 6. Helmsdale was another refreshment stop.

The train, a double locomotive, consisted of up to 14 carriages including sleeping quarters for officers and some compartments for prisoners. With such a long journey food was supplied for those travelling north to take up their deployment. Bagged teas were supplied to officers and at Inverness there was a sit down breakfast often catering for up to 460. An official refreshment stall at Dingwall served 134,864 cups of tea in this time.

On its route from Euston the train stopped only a few times to take on water ( steam trains in those days) and to allow men to be transported to other bases. Despite it being an incredibly long journey (700 miles)  it kept very much to time.. It had a winter and summer timetable. In the summer leaving Euston at 6.30pm to arrive in Thurso the next day at 3.30pm.  Comparing it to travel today by the same means there is very little difference in time taken.

Military Police frequently checked the train carriages which on the south bound route often contained survivors of shipwrecks.

In the winter snow was a problem and on 12th of January 1918 in a dreadful blizzard the Jellicoe Express and a rescuing snow plough became stuck a few miles outside of Thurso. The next day men walked into Thurso. It was a week before the line was cleared which meant running a train to Invergordon instead from where men were shipped north.

Delivering the mail to those serving on board the vessels of the Grand Fleet in Orkney was an extremely important function of the Jellicoe Express with sorting taking place on the northern part of the journey.

Once at Scapa Flow the  Imperious became the Post Office where mail was sorted and delivered to the awaiting vessels. Something like 50,000 letters and parcels a day were sorted 80 million in total being delivered over the period.  It provided banking facilities and also delivered English and Scottish newspapers – hot off the press  which were sold, profits going to the war disabled.

The last run for the Jellicoe Express was on 30th of April 1919 until it was resurrected for duties in World War 2.