The Thompson Q1 0-8-0T Locomotives
Withdrawal of the Q4 goods locomotives started in 1934, but was delayed by
a wartime shortage of goods locomotives.
Between 1942 and 1945, Thompson would rebuild
thirteen of these Q4s as tank engines for use as heavy shunters.
The rebuilds were given the classification of Q1, which had been made vacant by the withdrawal of the last
Ivatt Q1 in 1934.
Initially, Thompson's standardisation
plans did not include an 0-8-0T class, but by late 1941 plans were drawn up for an 0-8-0T to
replace an order for new J50 0-6-0T
shunters. This 0-8-0T was based on a rebuild of the Q4, and rebuilding started
almost immediately. The frames, cylinders, and connecting rods were kept. The boiler was shortened to
provide space for an fully enclosed cab and the bunker. With the firebox further forward, the
valve gear eccentrics had to be moved forward from the third axle to the second axle.
Building had already started on some of the parts for the cancelled
J50s. Some of these parts were incorporated
into the side tanks, cabs, and bunkers of the first Q1s.
Usually the weight was distributed so that it was highest on the main driving axles, but the
first four Q1s were unusual in that the weight was mainly on the two front axles (19tons maximum axle load).
The first four engines entered service between June 1942 and March 1943.
At a very early stage, there were complaints about the very small water capacity.
Hence, the later engines had a longer bunker and were designated Q1/2 whilst the original four were
designated Q1/1. The Q1/2s had their frames extended by 6 inches to enable the larger
bunkers. The coal capacity of the new bunkers was reduced by half a ton. The end result was an increase
in water capacity of 500 gallons. The larger bunkers also influenced the weight distribution. Unlike the Q1/1s, the
maximum axle load was on the rear two axles. Nine locomotives were built to the Q1/2 specification.
Although many of the original Q4s had superheaters, these were removed during
rebuilding. Steam brakes were fitted as standard, with a gradable steam brake fitted to all members of
the class between 1947 and 1948.
The new Q1s were tried in a number of places requiring heavy shunting work. They were more powerful than
the J50s, but not as powerful as the
T1 heavy shunters. Most were distributed
in the Southern Area, although a couple worked in the North Eastern Area and a couple worked in the
The Q1s were considered to have roughly equal power abilities as the
O4s but were seriously restricted by their
lack of water capacity. Although the Q1s showed mixed results at most of the yards where they worked,
they were used very successfully at Frodingham. Most of the traffic in the area serviced Scunthorpe's
steel mills, and a typical 0-6-0T shunter was far from adequate at shunting these heavy
loads. A Q1 could handle them very well, and there were plenty of opportunities to refill the
limited water tank.
Withdrawals started in 1954 and were completed by 1959.
Locomotive Nos. 9925-9928 (BR Nos. 69925-69929) were built as Q1/1.
The remaining locomotives (Nos. 9929-9937, BR Nos. 69929-69937) were built as Q1/2.
||1068 sq.ft. (228x 1.75in)
||1068 sq.ft. (228x 1.75in)
||(@ 85% boiler pressure)
||69 tons 18cwt
||73 tons 15cwt
|Max. Axle Load:
||19 tons 15cwt
||4 tons 10cwt
None of the Thompson Q1s survived into preservation.
A 4mm scale kit of the Thompson Q1 is available from Millholme.
Gladiator produce a 7mm scale (O gauge) kit of the Thompson Q1.
Thank you to the P.H. Groom collection for permission to use the above photograph of Q1/2 BR No. 69931.