The first locomotive superintendent was William Barclay, who was a nephew of Alexander Allan.
Only four of the Barclay era locomotives, all rebuilt by Jones, were still in service at the time of the Grouping in 1923.
The first locomotives were two 2-2-2s were supplied by Hawthorns and Company of Leith in 1855, and a second pair delivered in 1857.
2 received a more extensive rebuild, gaining a larger boiler and 15.5-by-22-inch (394 by 559 mm) cylinders, and lasted until 1899.
10 as a 4-4-0 to counter flange wear problems on the Dingwall & Skye line.
He used the Adams bogie arrangement and replaced the cylinders with new ones of 17 and 24 in (432 and 610 mm) bore and stroke.
7) was similarly rebuilt, although this seems to have been a trial for new features adopted for the Skye bogies.
The other 5 locomotives of this batch remained as 2-4-0s but were rebuilt with cabs and longer (24 in or 610 mm stroke) cylinders between 1875 and 1880.
12 was rebuilt by Jones as a 2-2-2T for branch line work, in which form it survived until 1898.
They were similar to but slightly larger than the earlier batch, and were fitted with cabs from new.
The next year, Sharp, Stewart supplied ten more, with the stroke increased to 24 inches (610 mm) but otherwise identical.
With increased traffic, especially over the Perth line, heavier locomotives were needed, but the company was short of money.
This is generally considered the basis of the LB&SCR "Terrier" locomotives he produced later in his career.
Alterations included thicker tyres to increase the wheel diameter to 3 feet 6 inches (1,067 mm), and the provision of larger bunkers.
As will be apparent, the original numbering scheme was a simple chronological sequence, although Stroudley tank no.
16 was built as a replacement for the original Findhorn branch engine and received its number.
Renaming of locomotives was common in the early years, and only the first name is recorded here.
Features that arrived during the 1860s and stayed until the Peter Drummond days were the louvered chimneys and counter-pressure brake.
It is usually considered to have been adopted to aid forward visibility for the driver (a rather different pattern of smoke deflector), but there is some evidence that the real reason was to reduce the chance of lineside fires (rather like the prominent 'stacks' of early United States designs).