The Highland Railway had taken over the Dingwall and Skye Railway in 1880, which traversed the northern part of the Scottish Highlands from east to west. Although it was not until 1897 that the last ten miles were extended to Kyle of Lochalsh, ending opposite the Isle of Skye, the line was not easy to negotiate. There were many inclines up to 1 in 50 and curves with a radius of 1.300 feet or less.

David Jones' Duke class, later known as the class F, did reasonably well on the track. However, since the 75.5-inch driving wheels were too large and the speed dropped too sharply on the inclines, locomotive number 70 was built in 1882 with 63-inch wheels. Like the class F, it had an outside frame, slightly sloping cylinders with the same dimensions and also the same valve gear. In addition to the downsized wheels, boiler pressure has been increased by ten psi to further increase pulling power. Now the number 70 could be used in front of both passenger and freight trains.

It was not until 1892 that Jones had four more built and his successor Peter Drummond procured four more until 1901. They were called “Skye Bogies” since their domain was the line to Skye and they had a leading bogie in contrast to the usual 2-4-0 express locomotives used in the UK at this time. The nine examples formed the only class on the Highland Railway to be built entirely in their own workshops at Lochgorm, Inverness. They were classified by the LMS in power class 1P, but were completely withdrawn and scrapped between 1922 and 1930.

Starting in 1898, Peter Drummond had eight 4-4-0 locomotives built by Dübs, which were intended for passenger and express service and had inside cylinders. They were named after Scottish mountains, all of which start with “Ben”. Nine more followed between 1899 and 1901 from the Highland Railway workshops at Lochgorm and another three were built by North British in 1906. These were soon called “Small Bens”, as from 1908 six locomotives with larger boilers were supplied by North British. The Small Bens and Large Bens had identical dimensions for the driving wheels and cylinders. In the LMS the Large Bens were phased out by 1937 and the Small Bens partially survived the early years of British Railways.

The River class was Smith's only design for the Highland Railway. They were the most powerful locomotives of this company, but exceeded the axle loads permitted there. Although Smith had designed the locomotives to induce as little hammer blow as possible on the rails, they were not allowed to be used and Smith was forced to resign.

However, they managed to sell all six locos to the Caledonian, where the rails were stronger. After minor changes to the loading gauge, they were successfully used in front of express goods trains and were subjected to a great deal of stress. After the takeover by the LMS, the calculation of the hammer blow was better understood and it was concluded that these locomotives could certainly run on the lines of the former Highland Railway. This in fact took place before the locomotives were retired between 1936 and 1946.

The Dukes of Sutherland operated a 17-mile-long railway in the north of Scotland, which, among other things, connected to mines. The third Duke had already received a small 2-4-0T tank locomotive from Kitson in 1871, which he used for private journeys. When the fourth Duke of Sutherland took office, he wanted a new locomotive.

This now had the wheel arrangement 0-4-4T and was delivered by Sharp, Stewart & Co. in 1895. Since its predecessor's locomotive had already been sold to the Highland Railway, the new one was again given the name “Dunrobin”, after the castle with the same name. It had a spacious cab to accommodate guests, some of whom also came from the royal family.

David Jones had ten 4-4-0 express locomotives built by Dübs in 1874, which were first called the Bruce class and later renamed the Duke class when another class with that name was introduced. Between 1876 and 1888 the Highland Railway built seven more at their own Lochgorm workshops in Inverness.

The appearance of the locomotives was characterized by the outside frames in which the outside cylinders were arranged at an angle in the same way as, for example, Jones' later "Skye Bogies". The chimney was louvred at the front, which was intended to improve the draft in the boiler. The machines from Inverness had a slightly smaller boiler, which had a higher pressure of 150 instead of 140 psi. 

In the new class scheme that Drummond introduced in 1901, they became class F. The Dübs machines were the first to be retired from 1907 because they were the oldest. Five survived until 1923, but no longer received an LMS number.