The reference for locomotives and railcars


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Caledonian classes 49 and 903 “Cardean”
Great Britain | 1903 | 7 produced
No. 904 is her first years in Carlisle
No. 904 is her first years in Carlisle
Kris Wilson / flickr

The Caledonian Railway had to operate many express trains with two 4-4-0 locomotives and also needed a helper locomotive at Beattock Summit. To improve this, McIntosh developed a 4-6-0 in 1903. Initially these were just two locomotives, numbers 49 and 50, which were based on the Dunalastair and had inside cylinders. Although these became the flagship of the CR, their performance was not outstanding and there were no sufficiently long turntables.

After longer turntables were built, McIntosh had five improved locomotives built, numbers 903 to 907. The 903 was the only one in the new series to be given the name “Cardean” and thus gave rise to the nickname of the class. All of them received a superheater in 1911, but due to the reduced boiler pressure they hardly had any noticeable increase in output.

However, since this reduced coal consumption, all of them were taken over by the LMS in 1923. There they were soon eclipsed by the LMS Compound and Royal Scot. They were retired between 1927 and 1933, with the exception of the 907, which was written off in 1915 after Britain's worst rail disaster.

ManufacturerSt. Rollox
Axle config4-6-0 (Ten-wheeler) 
Gauge4 ft 8 1/2 in (Standard gauge)St. Rollox (Narrow gauge)
Dimensions and Weights
Wheelbase28 ft 8 in
Fixed wheelbase15 ft
Total wheelbase56 ft 10 in
Service weight163,250 lbs161,068 lbs148,500 lbs
Adhesive weight123,200 lbs122,100 lbs123,000 lbs
Total weight286,720 lbs288,748 lbs276,180 lbs
Axle load41,440 lbs
Water capacity6,005 us gal
Fuel capacity13,440 lbs (coal)11,200 lbs (coal)
Power sourcesteam
Estimated power1,050 hp (783 kW)1,060 hp (790 kW)1,075 hp (802 kW)
Optimal speed27 mph30 mph32 mph
Starting effort24,990 lbf22,667 lbf21,349 lbf
Power Plant
Driver diameter78 in
Boiler pressure200 psi175 psi
Expansion typesimple
Cylinderstwo, 21 x 26 intwo, 20 x 26 intwo, 20 3/4 x 26 in
Grate area26 sq ft
Firebox area145 sq ft148.3 sq ft
Tube heating area2,255 sq ft2,315 sq ft1,665.8 sq ft
Evaporative heating area2,400 sq ft2,460 sq ft1,814 sq ft
Superheater area516 sq ft
Total heating area2,400 sq ft2,460 sq ft2,330 sq ft
Calculated Values
steam locomotive
John Farquharson McIntosh
last changed: 02/2024

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