It’s been a wet Bank Holiday here and, stuck indoors, I found myself thinking about what it was that made the ‘Fire Fly’ class so special. The following notes reflect my musings:
After all, these engines looked very similar to their immediate predecessors, the ‘Stars’ that the GWR bought from R Stephenson & Co. This similarity is obvious in the first engine photographs ever taken, which include ‘Polar Star’, outside Cheltenham shed in the late 1840s.
‘Polar Star’ photographed at Cheltenham c.1849
Thee were 12 ‘Stars’, of which ‘North Star’ became famous as the first reliable engine operated by the GWR. Even ‘North Star’ needed some adjustments to its draughting, carried out by Brunel and Gooch before it was able to achieve its true potential.
North Star replica – Steam Museum Swindon
‘North Star’ and its sister ‘Morning Star’ were bought from stock that had originally been ordered by other railways but were not delivered. They were rather hastily adapted to the Broad Gauge and ‘North Star’ was given 7 foot diameter wheels in an attempt to meet Brunel’s low piston speed requirement. On the other hand, ‘Morning Star’ retained it’s original 6’ 6” driving wheels.
It was typical of the time that only rough sketches were made of the alterations required. As Brian Arman comments in Part 1 of his survey of Broad Gauge engines: “it was probably only intended as a general diagram to demonstrate to the shop floor staff the new frame and axle arrangements … The practical adjustments and decisions by which these changes should be made were left to the skilled shop floor staff” This epitomises the way in which construction proceeded at that time.
In addition, the RCTS ‘Locomotives of the GWR, Part Two’ makes the comment that: “While of the same general design with slotted outside frames these engines differed from each other in detail”. I think that this is a key point, when we compare these engines with the the Fire Fly class, designed by Daniel Gooch.
A Variety of ‘Stars’
To demonstrate how different these ‘hand built’ engines used to be, I looked through all the information about the Stars, provided in Brian Arman’s comprehensive series ‘The Broad Gauge Engines of the Great Western Railway’ [which I strongly recommend] and picked out a little from there to make the following table:
* Polar Star was the first to be fitted with flanged driving wheels
(?) indicates the engine was stated to be similar to another engine
Note that four years elapsed between the first and the last, and that ‘Fire Fly’ was delivered in March 1840, when only the first four ‘Stars’ had been delivered.
The boilers of Rising Star and Bright Star were 2 feet longer than the earlier engines. Following them, Shooting Star is described as similar to Evening Star, suggesting a reversion following some experimentation. Shooting Star did, however, differ in having a lower top to the firebox casing, with the manhole on the flattened top rather than at the front, as on the other engines.
Did schoolboys of the time vie with each other in recognising individual engines as they passed by on the line?
Many of these engines were re-built before the end of the 1840s and several became 4-2-2T engines. We are very fortunate that E.T. Lane, a pupil at Swindon in the 1840s, who sadly died at the age of 20, made several sketches of Star class engines in their original form. These give a good impression of the amount of variation between some of these engines.
‘Evening Star’ as sketched by E.T. Lane
Note the Haycock firebox in place of the round-top of ‘North Star’
Rising Star as sketched by E.T. Lane
Note the lengthened boiler and wheelbase
Royal Star drawn by E.T. Lane
Note the Gothic-style of firebox
As noted above, none of these engines kept its original appearance for long. Compare the following photo of ‘North Star’, taken after its re-building in 1854, with my photo (above) of the replica in the Swindon Museum.
North Star photographed at Swindon in 1871
The Gooch Revolution
Daniel Gooch had taken on the role of locomotive superintendent of the GWR, a few days before his 21st birthday. He soon found that he had a very motley collection of locomotives, with which he had to try and run a train service. He was heavily criticised by some members of the GWR Board but had the courage to write a detailed appraisal which, in turn, was highly critical of decisions taken by his boss – Brunel! He won through and absorbed the lessons he learned from struggling to maintain a fleet of engines, within which each member had its own problems and there were no ‘common’ solutions.
He put this knowledge to good use,when he planned ahead to meet the great expansion that was to be needed, once the line was completed through from London to Bristol. He had to order a large number of new engines from several different manufacturers, because no one supplier had the capacity to meet his requirements. In doing this, he introduced the idea that components had to be standardised and he went so far as to provide templates, which each manufacturer had to use in order to ensure commonality.
This was the true revolution that he started with his Fire Fly class – they were a true ‘class’ that could be maintained be means of common adjustment techniques and by drawing from a store of spares that would fit whichever engine needed them. Thus, mechanics who could service one of these engines would have no trouble in dealing with any of the others. This was the start of modern ‘production’, leading eventually towards Henry Ford’s mass production techniques.
His experience had also taught him where the weak points lay and, hence, he paid special attention to these by demanding new processes, such as ‘steeling’ or hardening of surfaces, where wear could be expected in service.
I expect he met some resistance from those staff who were used to ‘doing their own thing’ and several of the engines he received were rejected because his instructions had not been followed. Gooch was tough enough to insist that his requirements had to be met, although he was also ready to accept suggestions for improvements, when these were justified It was by these means that the ‘Fire Fly’ class became the successful engines that they undoubtedly were.