Caledonian 4-6-0 Locomotives in Great_Britain

Class 179 (Locobase 20314)

Data from "4-6-0 Superheater Goods Engine, Caledonian Railway", Locomotive Magazine, Volume XX [20] (14 Februrary 1914), p 46; and "4-6-0 Express Goods Engines, Caledonian Railway", Railway Engineer (April 1914), pp. 104-106.

One of James McIntosh's last locomotive designs for the Caley was this quintet of superheated updates of the famous 1906 "908" class engines (Locobase 8363). (RE noted that McIntosh was due to retire in May 1914 because of an age-limit rule.) Other than the superheater, little had changed except for 1/2" (12.7 mm) increase in cylinder diameter, but the Robinson installation contributed a higher than usual amount of area than was found in most locomotives at the time.

Class 191 - New Oban bogies (Locobase 20964)

Data from "4-6-0 Passenger Locomotive, LM & SR [sic] (Caledonian Section)", Locomotive Magazine, Volume XXIX [29] (15 October 2021), p 305. See also "Caledonian Railway 191 Class" in Wikipedia at [], last accessed 30 November 2021. Works numbers were 22955-22962 in 1922.

Locobase 9475 describes the 1902 nonet of Ten-wheelers specifically intended by J F McIntosh for scaling heavily graded passenger-train routes. Twenty years after the first engines went into service, William Pickersgill apparently reasoned that the design needed tweaking, but not a thorough overhaul.

Thus the "New Oban" bogie 4-6-0s retained flat slide valves and didn't include a superheater. The tweaks consisted of increasing boiler pressure by 15 psi, and driver diameter by 5" (127 mm), increasing cylinder diameter by 1/2" (12/7 mm), slightly reworking of the firebox, trimming the tube lengths by a little more than five inches.

Soon after they entered service on the Callender-Oban section, the Caledonian was almalgamated into the London, Midland and Scottish Railway. Wikipedia comments that the locomotives could run short of steam "unless skillfully fired" and questioned why a main-line passenger engine could be built without a superheater in 1922. Citing Atkins (Atkins, C. P. (1976). The Scottish 4-6-0 Classes. Ian Allan, Limited.), the online encyclopedia adds that the class owned "the dubious distinction of the highest total locomotive hammerblow of any locomotive class inherited by the LMS upon its formation in 1923"

As a consequence of these shortcomings and the resounding success of the numerous Stanier"Black Fives" introduced in the 1930s, six went to the ferro-knacker's in 1939. Three of the other four were withdrawn in 1943 with only 14621 remaining until December 1945.

Class 49 (Locobase 2302)

Data from Ahrons (1927) for data and Angus Sinclair (ed) Railway and Locomotive Engineering, June 1903, p. 253 for further comments from "S.A.F". See also "Six-Wheel Coupled Passenger Locomotive; Caledonian Railway", Engineering (London), Volume 76 (18 September 1903), p. 399.

One of several 4-6-0 designs with inside cylinders, this JF McIntosh offering wound up with" a somewhat short connecting rod and an undesirably long wheelbase and boiler barrel" according to Glover (1967).

Hollingsworth (1982) summarizes McIntosh's rationale for staying with inside cylinders: "[t]he better riding and aesthetics given with the cylinders and motion inside the frames more than balanced the handicap of inaccessibility, as well as the extra costs involved in making a crank axle." SAF, reprinted in the R&LE, observed that the total heating surface of 2,400 sq ft "...could easily have been exceeded, but Mr.McIntosh has used flues of a large diameter [13 2 1/4" tubes] for the lower rows, where there is a liability of choking."

OS Nock contends (RWC III, pl 175) that these two engines, had boilers among the largest in Great Britain at the time and were designed to move 300 tons up Beattock Bank, which ran for 10 miles at a nearly continuous 1.3% grade. SAF reported that the reported engine weight of 168,000 lb was "...greater than that of the average British goods engine and tender combined." Engineering described the engines' solo runs up Beattock Bank pulling the midnight sleeper train and the 2 o'clock trains. The latter usually consisted of 19 1/2 to 20 1/2 vehicles on the up train, 16 1/2 vehicles on the down train and "these engines have proved they can haul this heavy load with ease."

Class 55 "Oban bogies" (Locobase 9475)

Data from Bulletin of the International Railway Congress (P. Weissenbruch, 1902), p. 990, reprinting from Engineering (29 August 1902).

The Engineering article explains J F McIntosh introduced these inside-cylinder freighters to handle the "special conditions" of traffic over the Callander and Oban lines. Not intended to handle main-line express traffic, the class rode on short coupled and engine wheelbases imposed by the steep grades and tight curves of the section.

55-59 were delivered in 1902, 51-54 in 1905.

See Locobase 20964 for Pickersgill's 1922 updates known as the "New Oban Bogies".

Class 60/4P-H (Locobase 2331)

For data see E C Poultney, "Recent Locomotive Practice on the Caledonian Railway - Part I", Engineer, Volume 132 (4 November 1921), pp. 474-476. See also "Six-Coupled Superheater Express Locomotives: Caledonian Railway", Volume XXIII [23] (15 March 1917); and Ahrons.

William Pickersgill's inside-valve (9"/179 mm piston), outside-cylinder six-coupled express. Compared to the 1903 class (Locobase 2302), this was a smaller engine.

Steamindex's editors cite Atkins, P. West coast 4-6-0s at work. 1981. Chap. 10. From 4-4-2 to 4-6-2 at St Rollox to buttress the point that these "Greybacks" were a disappointing quintet. Poultney's detailed analysis of the class suggests a key reason for their shortcomings when he notes that the maximum height allowance (to top of chimney) was 12 ft 10 1/2 in (3.92 m) and the boiler centerline was only 8 ft 6 in (2.59 m) above the rail.

This is low even by British standards, he argues, and was of "very great importance" in boiler design, limiting as it did boiler diameter, "but, what is perhaps of greater moment, it increases the difficulty in providing adequate fire-box [sic] dimensions and grate areas." This was especially inhibiting in express engine design, where driver diameter was necessarily only "moderate" if the firebox (and grate width) was to extend over the drivers. (An earlier Locomotive Magazine report on an earlier locomotive said that the transverse loading gauge (i.e. one that gave a practical maximum width for a British locomotive) effectively prohibited outside cylinders of greater than 22" diameter.)

Atkins reported that against the the Preston to Carlisle tests against a Prince of Wales class 4-6-0 in 1925/6 on the Preston to Carlisle section, the 60s proved to have a thirst for lubricating oil and a relatively high coal consumption. Lb/drawbar horsepower came to 4.84 for the Class 60 and 5.05 for the Prince of Wales, which looks good for the 60s, but when measured in lb/mile, the 60s wolfed down 51.55 lb/mile vs 48.3 lb/mile for the Prince of Wales.

Although presumably uninspiring, the five engines were serviceable enough to be taken into the LMS at Grouping in 1923 and into British Railways in 1948.

Hughes built 20 to a modified design in the 1920s.

Class 908 / Sir James F King (Locobase 8963)

Data from J F Gairns, "Some Remarkable Locomotives of 1906", Cassier's Magazine, Vol XXXII, pp.144-159. See also Steamindex's section on Caledonian locomotives ([])

Steamindex claims this class was based on the Cardeans (Locobase 9083), but the data suggest that the lineage extends back to the Oban Bogies described in Locobase 9475. A significant difference was the use of 2" tubes in place of the 1 3/4" tubes in the earlier engines. Yet another variation in J F McIntosh's basic Ten-wheeler design, this class had taller drivers than the freight-traffic 918s (Locobase 10583) and much lower drivers and smaller boiler than the Cardeans (Locobase 9083).

Class 918 (Locobase 10583)

Data from "Six-Coupled Bogie Goods Locomotive, Caledonian Ry" The Locomotive Magazine, Vol XII (15 September 1906), p.147.

James F McIntosh obviously found a boiler and grate combination that was satisfactory and varied the details to suit particular segments and alignments. The Cardeans (Locobase 9083) handled express duties, the 908s (Locobase 8963) were devoted to mixed traffic, and this quintet were the mountain climbers. Boiler tubes varied in length but the firebox and power dimensions remained the same.

The 918s followed the pattern of the Oban class (Locobase 9475) in being driven from the front axle, which reduced the inclination of the inside cylinders.

Class 956 (Locobase 2335)

Data from"Caledonian Railway", Locomotive News and Railway Notes, Volume VIII [8], No 45 (10 January 1921), p. 12. See also "Three Cylinder Express Locomotives, Caledonian Railway, Locomotive Magazine, Volumes XXVII [27] (15 August 1921), pp. 194-195; XXVIII [28] (15 June 1922), pp. 157-159.

William Pickersgill's three-cylinder simple-expansion six-coupled express. The earlier of the two LM reports noted that the relatively narrow transverse loading gauge (i.e. one that gave a practical maximum width for a British locomotive) on most main line effectively prohibited outside cylinders of greater than 22" diameter.) Putting big cylinders inside the frames exposed cranks, big ends, journals and the like to "great piston loads". With three cylinders, claimed the optimistic designers,"this trouble disappears"

The outside cylinders drove the middle axle, the inside one cranked the leading axle. Although Glover (1967) comments that the tube length is a relatively long 16 feet, he notes earlier that the 1903 Class 49 had tubes 3" (72.2 mm) longer. [It should also be noted that the tube diameter/length ratio was 96, very close to what many designers considered the ideal ratio of 1:100.] Glover adds that these were the largest locomotives ever built for the Caledonian.

Steamindex ([], last accessed 23 August 2008) reports that these were considered to be failures. The editors quote from Atkins, P. West coast 4-6-0s at work. 1981. Chap. 10. From 4-4-2 to 4-6-2 at St Rollox, summarizing: "Atkins considers that George Kerr was responsible for the design, especially the conjugated valve gear. Graeme [G.R.M.] Miller informed Atkins that the substitution of Stephenson link motion for the inside cylinder was due to the very high reciprocating mass of the derived gear. The derived moion was modified with dashpots which led to an extraordinary sound. Atkins argues that in this final form the class was the only one to enter the LMS which combined long travel with long lap, but the performance of the class was limited: 24,000 miles/year as against 32,000 miles for the class 60"

The Steamindex editors also quote, with apparent delight, from Cox, E.S. Chronicles of steam. 1967. page 170 about the physical and operational oddities of this design: "The first time I found myself hauled by one of the ' 956 ' class of 3-cylinders 4-6-0's I could not believe what my ears told me was happening up front, and when, in due course, this cacaphony with its attendant ills was too grievous to be borne due to the erratic behaviour of the conjugated gear, the effect of the introduction of a separate Stephenson valve gear for the inside cylinder having variable lead, together with retention of the outside Walschaert valve gears having fixed lead, could only produce results at which the mind was bound to boggle".

Wikipedia's 956 entry chips in with several other defects: "Draughting was a problem from the beginning, and firemen had a lot of trouble keeping them up to pressure. There were other troubles thought to be a result of too small an ashpan causing choking of the grate.

"The valve gear was insufficiently robust and the valve spindle guides (originally cast iron) had to be replaced in cast steel."

Given that most railways would hold onto their locomotives as long as mechanically possible, it's a mark of the LMS's inherited distaste for this class that the last of them was withdrawn by 1935.

Class Cardean (Locobase 9083)

Data from Fowler, Illustrated Locomotive Dictionary (1906), p 506 and "Six-Coupled Bogie Express Locomotive, Caledonian Ry", The Locomotive Magazine, Vol XII (14 July 1906), pp.108-109.

One of several 4-6-0 designs with inside cylinders from John Farquharson McIntosh. This elaboration of the 1903 Ten-Wheelers had a boiler diameter of 63 1/2", a slight increase in firebox heating surface to 148 sq ft, and main rods of 82" versus the 78" of the earlier engines. In addition, says Glover (1967), McIntosh lengthened the driving wheel bearings by using smaller cylinders (which put the cranks closer to the centerline) and adopting drivers that dished out toward the hub. According to the LM report, one key change from earlier Caledonian engines was the adoption of larger bearings, which measured 9 1/2" diameter by 10 1/2" long in the driving axle. The other coupled axles had bearings with a concave profile in which the outer ends were 9 1/2" in diameter and the center 8"; these were 12" long. In addition, the big end's bearing was 9 1/2" in diameter by 4 3/4" in length.

The Cardean became well-known as the personal engine of David Gibson, the driver of the daily Corridor express from Glasgow to Carlisle (and return). Not superheated when new, they were fitted with a good amount of superheat surface in 1911-1912; see Locobase 2577.

Class Cardean - superheated (Locobase 2577)

Data from Brian Hollingsworth, The Great Book of Trains (New York: Crown Publishers, 1987), pp. 86-87.

A good-sized Ten-wheeler design when produced with saturated boilers in 1906 (see Locobase 9083), the Cardeans were fitted with a good amount of superheat surface in 1911-1912.

907 headed the Glasgow Express northbound when it was wrecked in the Quintinshill disaster on 22 May 1915. A troop train on the northbound track hit a local passenger train because of errors committed by two signalmen. Flimsy carriages crumpled and gas canisters exploded, killing 210 members of the 1/7th Batallion of the Royal Scots Regiment and injuring 224 others. Three crew on the troop train, a woman and her infant son were killed on the local train, the engineer and nine others died on the Express.

The others survived until the late 1920s, with Cardean herself (the only named engine) lasting until 1930.

Class River (Locobase 3768)

Data from Bryan Attewell ([] Steam locomotive simulator (April 2000 edition). See also Wikipedia's "Highland Railway River Class", last accessed at [], on 11 September 2018; "4-6-0 Mixed Traffic Locomotives: Caledonian Railway", Volume XXIII [23], No 294 (15 February 1917); and Steamindex, [], last accessed 27 June 2009. Works numbers were 3095-3100.

This class was designed by Frederick G Smith of the Highland Railway and entered service on that line. Soon after they were introduced, however, they were found to be too heavy for some of the bridges. Smith protested vigorously, noting that his efforts to reduce hammer blow on the rail brought the Rivers in line with previous Highland 4-6-0s. The catalogue of miscommunication and unexamined assumptions that led to the rancorous dispute between Smith and Alex Newlands, the line's chief engineer, the involvement of North British Railway and North British Locomotive Company in the design runs for pages. See Steamindex's summary of Highland locomotives for citations and excerpts.

The upshot was that the Rivers never operated for very long on the Highland. Only the first two apparently bore their intended names--Rivers Ness and River Spey--in service. The other four were to have been named: Rivers Tay, Findhorn, Garry, and Tummel.

Rejected by the HR, the sextet was sold to the Caledonian. On this railway, the class found a home at a time when the Caley was short of power to work the burgeoning war traffic. Described in the 1917 LM report as "fine machines", they are reported by other sources to have been well-liked by their crews as they handled heavy goods traffic between Aberdeen and Carlisle.

LM described the Smith patent feed water heater licensed from its designer by Messrs Mead, Mclean & Company of London. Installed in the smoke box, the device was a "flat case through which pass a number of tubes which correspond in position and size with the boiler smoke tubes, the gases flowing freely through them."

By the 1920s Smith's intentions were better understood and proved valid and this class, now under the LMS, was reassigned to the ex-Highland main line service for which they were originally designed. The reunion of locomotive and service now accomplished, the class served the LMS for another 20 years.