By Alan Crossfield

The late J. N Maskelyne opined that The GWR Dean Single Achilles Class was ”one of a class of 80 express passenger engines which to me, when a boy, were almost sacred. They stood apart from all other engines, and they achieved the summit of beauty in locomotive design.”

Writing in the late 1950s he added: “ I will not argue on this matter; my opinion was formed just 62 years ago and has remained unaltered ever since - against the test of time and an ever growing appreciation of the finer details of locomotive anatomy.”

He was not so keen on some of the later modifications to these engines.

A Dean Single can be found on Swindon’s coat of arms.

The Dean Single has, of course, been modelled many times in every gauge, including John Clarke in 7.25”  and 5” by Pete Rich. Both designs are available.

This model of 3050 Royal Sovereign is in 5” gauge to his usual amazing high standards by Alan Crossfield and was shown at the 2019 Doncaster exhibition.

The first 30 members of the class were built as 2-2-2s of the 3001 Class. The first eight of those were built as convertible broad gauge 2-2-2 locomotives, and converted to standard gauge in mid-1892, at the end of broad gauge running. A further 22 were built in late 1891 and early 1892, this time as standard gauge engines. later engines, 3031 to 3080 were built between 1894 and 1899, fitted with larger boilers whose diameter was limited by its position between the 7’ 8.5” drivers.

The steam chest was located (conveniently for modellers) underneath the cylinders. The steam chest and valves lay above the front carrying axle, and there was sufficient clearance to allow the steam chest cover to be removed over the axle for maintenance.

A bogie of conventional design would have obstructed access to the port faces. Dean used a suspension bogie, in which the weight of the locomotive was transferred upwards to the bogie by four bolts mounted on the inside frames. The centre pin of the bogie rotated in a spring-centred block mounted beneath the steam chest on cross beams.

None of the original class survive, but a static replica of The Queen was commissioned for a Railways and Royalty exhibition at Windsor and Eton Central railway station. The engine remained there, but the tender was scrapped to make more space for a shopping centre occupying that station building.

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