Following my recent post about research into the ‘Fire Fly’ class engines, @Mikkel remarked “I was wondering when and why Gooch abandoned the Haycock firebox for his own round topped version, e.g. on the Pyracmon class.”

my model of ‘Tantalus’

It reminded me that, when I was preparing my model of ‘Tantalus’, one of Gooch’s ‘Standard Goods’ engines, I had collected together a number of drawings by G F Bird of various engines from this class and its immediate predecessors.

Taken together, they serve to illustrate the line of development from the very first engine to emerge from the new Swindon Works in February 1846. The boiler of this 0-6-0 engine ‘Premier’ was supplied from outside, so it was not entirely ‘home grown’ – that honour went to the remarkable ‘Great Western’ 2-2-2, completed in April of the same year.

Premier was the first of a batch of 12 similar engines built throughout the following year and, as with most ‘hand built’ products of the period, there were differences in detail between the various individuals. These engines all retained the early features of wooden strips lagging the boilers and the ‘haycock’ style cover over the inner-firebox, to provide a steam collecting space. The driving wheels were 5’ 0” diameter, which was to remain the same throughout GWR history, although thicker tyres were used much later. The average weight of this lot was 26¾ tons.

Premier (built Feb. 1846)

The next batch of six engines, headed by ‘Pyracmon’ in November 1847 (the name means ‘fire anvil’ and comes from Virgil’s Aeneid) started what was to become a steady process of enlargement and, most significantly, saw the abandonment of the ‘haycock’ firebox, substituting the ‘round topped’ firebox that characterised all Gooch’s later designs and was to re-appear, in Dean’s time, in the famous 4-2-2 ‘Singles’. The weight was now 28 tons 3 cwt.

Pyracmon (built Nov.1847)

The enlargement continued in the eight engines of the ‘Caesar' group, beginning in June 1851.  The weight of these engines was now 32 tons 9½ cwt. These engines were generally very similar to the later engines that became known as the ‘Standard Goods’.  The cylinder stroke was lengthened by 1” to 17 inches. The wooden boiler cladding was now replaced (or supplemented) by a painted iron cladding.  In the book ‘Railway Machinery’ by D.K. Clark (published in 1855), there are the following notes on Cleading [sic]: "The boiler should be completely enveloped, at all approachable points, in a non-conducting garment, consisting of several plies of felt, covered with ¾ inch pine battens grooved and tongued, and finished with sheet iron, No. 17 wire gauge, strapped well down.”

Hero (built Dec.1851)

Someone once remarked that the nice thing about ‘standards’ is that there are so many to choose from. This was true of the various batches of ‘standard’ goods, which continued to follow a pattern of ‘continuous improvement. The need for more goods engines was clearly expanding rapidly, as 102 of these engines were built in seven lots, the first batch being known formally as the 4th lot goods (following the ‘Caesar’ group, which were the 3rd lot). The first of these engines was completed in May 1852 and subsequent lots were produced until March 1863, so they covered the whole of the remaining ‘Gooch’ period of the GWR.

Cato (built Mar.1853)

Successive lots still showed detail improvements, such as re-arrangement of the equalising beams between the springs of the suspension, as shown in the following drawing, which is based on one of the illustrations in Gooch’s notebook. By the time of the 7th lot, welded plate frames had been introduced.

7th lot Goods (from Aug.1857)

Of all these engines, only ‘Europa’ (5th lot) was rebuilt*, in 1869, and survived until the end of the Broad Gauge, when it had the distinction of being the last Broad Gauge engine to leave Plymouth for Swindon on 31st May 1892.

The overall layout continued with little change in the later series of ‘Standard Goods’ produced by Joseph Armstrong as the ‘388’ class.  By now (1866) the Gifford injector had replaced mechanical pumps for the water feed to the boiler and modern innovations such as cabs and domed boilers were being applied.  Although these engines were built for the standard gauge, 20 were converted to Broad Gauge in 1884-1888, to head goods traffic between Plymouth and London during the final years of the Broad Gauge, as shown below:

These illustrations show that there was a continuous line of development of GWR 0-6-0 engines, from ‘Premier’ of 1846 through to the Armstrong and Dean versions and, with a few more ‘modern’ innovations, to the Collett Goods of the 1930s.

*  @Annie has posted a good photo of the rebuilt 'Europa', showing the sloping front to the smokebox.

Mike