LMS 2-6-4 Locomotives in Great_Britain


Class Details by Steve Llanso of Sweat House Media

Class 4P-E (Locobase 3756)

Data from [link], last accessed 18 February 2021; and "LMS 2-Cylindered Stanier 2-6-4T", Wikipedia at [link], last accessed 21 February 2021. The LMS's ex-Midland Derby shops produced 133 and North British Locomotive Company supplied 73 more in 1936 (works numbers were 24301-24365) and 1937 (24366-24373).

Although Stanier had adopted Fowler's three-cylinder 2-6-4T (Locobase 12484) with only slight tweaks, he only completed 30 of that version.

The last seven had two cylinders because Stanier was already looking ahead to large classes of locomotives that could operate practically anywhere in the LMS system. So he introduced a modified Fowler design with Stanier's tapered boiler and two cylinders rather than three. Each cylinder's diameter increased by 3 5/8" (92 mm). Together, the two presented virtually the same volume as the total from three smaller cylinders.


Class 4P-F (Locobase 3757)

Data from [link], last accessed 10 May 2008; " Tank engines - 2-6-4T " at [link], last accessed 21 February 2021; and Bill Horsfall, London Midland & Scottish (Bloomington, IN: Author House, 2014), pp.54-55

This was one of two William Stanier designs for this wheel arrangement. Stanier built 30 more of Fowler's very successful parallel-boiler design (Locobase 12484) as a "halfway stage before the taper boiler version" to meet demand on the former London, Tilbury & Southend. In addition to the double-window cabs, Stanier mounted wheels with triangular rims and built-up balance weights, and used side bolster bogies and bissel trucks.

[link] (visited 2 September 2004) observes: "Powell [Stanier locomotive classes. 1991] notes that the two-cylinder 2-6-4T was barred from Fenchurch Street, but that a three-cylinder design wiith improved balancing and reduced hammer-blow would be acceptable to the LNER's Civil Engineer (although Powell failed to recognize the significance of this aspect). It was also considered that the three-cylinder design would give improved acceleration and Powell considered that the design 'proved ideally suited to the difficult conditions on the Tilbury section'"

Underscoring the quality of Stanier's design was a long-term observation of LMS workings along the former LTS line in the 1930s. Bill Horsfall recorded the 2-6-4Ts both in words and film that showed just how much of an improvement they represented. According to Horsfall, "[t]he many intermediate stops demanded hard acceleration and, in dry conditions" the engines could haul twelve-coach trains "in full gear with wide regulator with wide regulator for half-a -minute without slipping, that is, 'all out', completely outclassing the Derby 4-4-2Ts."

Unlike the two-cylinder version, however, this one was not consulted when British Railways built a 2-6-4T (Locobase 1481). They continued in service throughout the 1950s, In 1960, one engine was withdrawn. It was followed by seven more in 1962 and all 29 remaining engines in 1962.


Class Fairburn 4P/4MT (Locobase 20846)

Data from "LMS Fairburn 2-6-4T" in Wikipedia at [link]. See also"Charles Fairburn and his 2-6-4T" at [link], last accessed 25 June 2023; "Ex-LMS Fairburn Class 4 2-6-4T" on the estimable Southern Railway E-Mail Group's website at [link]; and "

4MT 42050 - 42299 & 42673 - 42699 2-6-4T LMS Fairburn

42050" at [link]. (All sources last accessed 25 June 2023.).

Locoyard's team point out two surprising facts about LMS's Chief Mechanical Engineer Charles Fairburn: he served for only a year after his 1944 appointment and this was his only steam locomotive design. His interest lay much more in the development of diesel and electric rail traction from the time he worked for Stanier beginning in 1934.

Indeed, when the LMS needed to upgrade its stud near the end of World War II, Fairburn drew from Stanier's 1935 2-6-4T (Locobase 3756 ). He shortened the Stanier's wheelbase, decreasing the curve radius from 6 chains to 5 and shaving 3.4 long tons (6,720 lb) as a result. Of the 227 built between 1945 and 1951, 41 of the Fairburns were erected in the Southern Railway's Brighton shops in 1950-1951.

Adopting the wheel arrangement came despite the Southern's lingering horror at the memory of the 1925 Sevenoaks disaster that was blamed on a leading truck under a heavy tank (see Locobase 2357). "[I]t was clear," wrote SEMG, "that the latest LMS 2-6-4T locomotives seemed to have a good pedigree." Like other Stanier designs, the LMS 4C boiler presented a prominent Belpaire firebox, small steam domes and large, transversely mounted sandboxes, and short tanks.

A "favorite stamping ground" included the Maidstone to Ashford run.

Years after Fairburn died of a heart attack in 1945. death, R[obert] A Riddles considerably modified the 4MT design to arrive at the British Standard 4 class.(Locobase 1481).

All 277 locomotives appeared on the British Railways roster in 1961, but withdrawals began in the same year.. BR drew the class steadily until the last left in 1967. Two Brighton-built Fairburns survived to operate on the Lakeside & Haverthwaite heritage railway.

The first 96 were delivered with tanks carrying 2,250 US gallons (8,520 litres) of water.


Class Fowler 4P-D/MT (Locobase 12484)

Data from [link], last accessed 17 April 2011. See also [link], quoting inter alia A[lec] J[ohn] Powell. Stanier locomotive classes (London: Ian Allan, 1991), Ernest Stewart Cox

Fitted with long-lap, long-travel valves, this large class of tank locomotives used the pony truck design first encountered by predecessor Midland Railway in the Schenectady Moguls delivered in 1899 (Locobase 9510). They also incorporated a parallel boiler design

Steamindex comments that this design "...was the one of the few Fowler designs used by Stanier as a direct basis for his own developments." Certainly the ratios speak of great potential: relatively high superheating ratio, big Belpaire firebox and grate, relatively high drivers that allowed the engine to hit speeds of up to 90 mph pulling a train.

Powell appears in steamindex's summary to support that view: "In 1927 Fowler introduced some highly successful parallel boilered 2-6-4T locomotives to handle heavy suburban passenger trains. With an excellent boiler and long-travel [6 3/8"/162 mm] Walschaerts valve gear they proved to be very speedy and were more than once timed at 90 mph [145 kph], despite coupled wheels of only 5ft 6in diameter. Clearly this was a design which Stanier could endorse, but which could not be redesigned immediately to incorporate his own ideas."

The class enjoyed long careers with the first five being retired in 1959 and the last two in 1966.

Principal Dimensions by Steve Llanso of Middle Run Media
Class4P-E4P-FFairburn 4P/4MTFowler 4P-D/MT
Locobase ID3756 3757 20846 12484
RailroadLMSLMSLMSLMS
CountryGreat BritainGreat BritainGreat BritainGreat Britain
Whyte2-6-4T2-6-4T2-6-4T2-6-4T
Number in Class20637277125
Road Numbers42425-44294, 42537-42672250-2536/42500-425362187-2273, 2673-2699/42050-42299+2300-2424
GaugeStdStdStdStd
Number Built20637277125
BuilderseveralDerbyseveralDerby
Year1935193319451929
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.50 / 4.7216.50 / 4.7215.33 / 4.6716.50
Engine Wheelbase (ft / m)38.50 / 11.7338.50 / 11.7337.08 / 11.3038.42 / 11.71
Ratio of driving wheelbase to overall engine wheelbase 0.43 0.43 0.41 0.43
Overall Wheelbase (engine & tender) (ft / m)53.23 / 16.2237.08 / 11.3038.42 / 11.71
Axle Loading (Maximum Weight per Axle) (lbs / kg)40,208 / 18,238
Weight on Drivers (lbs / kg)115,024 / 52,174127,680 / 57,915118,720 / 53,851
Engine Weight (lbs / kg)196,784 / 89,260209,888 / 95,204190,960 / 86,618193,200 / 87,634
Tender Loaded Weight (lbs / kg)122,416 / 55,527
Total Engine and Tender Weight (lbs / kg)319,200 / 144,787
Tender Water Capacity (gals / ML)2400 / 9.092400 / 9.092400 / 9.092400 / 9.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 4.40 / 44 / 4 3.90 / 3.50 3.90 / 4
Minimum weight of rail (calculated) (lb/yd / kg/m)64 / 3271 / 35.5066 / 33
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 175369 / 175369 / 175369 / 1753
Boiler Pressure (psi / kPa)200 / 1380200 / 1380200 / 1380200 / 1380
High Pressure Cylinders (dia x stroke) (in / mm)19.63" x 26" / 499x66016" x 26" / 406x660 (3)19.63" x 26" / 499x66019" x 26" / 483x660
Tractive Effort (lbs / kg)24,684 / 11196.4924,598 / 11157.4824,684 / 11196.4923,125 / 10489.34
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.66 5.19 4.81
Heating Ability
Tubes (number - dia) (in / mm)157 - 1.75" / 44
Flues (number - dia) (in / mm)21 - 5.375" / 137
Flue/Tube length (ft / m)12.25 / 3.7312.25 / 3.7312.25 / 3.73
Firebox Area (sq ft / m2)143 / 13.29137 / 12.73143 / 13.29138 / 12.83
Grate Area (sq ft / m2)26.70 / 2.4825 / 2.3226.70 / 2.4825 / 2.32
Evaporative Heating Surface (sq ft / m2)1366 / 126.911011 / 93.931366 / 126.911220 / 113.38
Superheating Surface (sq ft / m2)230 / 21.37160 / 14.86230 / 21.37266 / 24.72
Combined Heating Surface (sq ft / m2)1596 / 148.281171 / 108.791596 / 148.281486 / 138.10
Evaporative Heating Surface/Cylinder Volume149.99111.40149.99142.99
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5340500053405000
Same as above plus superheater percentage6088570060885900
Same as above but substitute firebox area for grate area32,60431,23632,60432,568
Power L110,483794710,48311,602
Power MT602.77411.66584.01

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