Data from Ahrons (1927); and "The London Tilbury and Southend Railway", (29 May 1909), p. 2671. See also "3P 41928 - 41978 (LTSR 37 & 79 Classes) 4-4-2T LTSR Whitelegg Tilbury Tank" on the Preserved British Steam Locomotives website at [], last accessed 8 October 2022. Robert STephenson & Company works numbers were 3366-3369 in 1909, Derby Works delivered ten in 1923, Nasmyth, Wilson five in 1925 (works numbers were 1448-1452 in 1925), then 20 from Derby in 1927 (10) and 1929 (10).
Later version of Adams' outside-cylinder tank engine by T Whitelegg; this was an enlargement of the first Whiteleggs of 1893 (see Locobase 5703). Classic suburban tank locomotives, these could reach 65 mph (105 kph).
The PBSL website's account of the 79s and successors looked at the continued production the LTS design and concluded: " The construction of non-superheated passenger tank engines as late as 1930 was an anachronism, (although the LMS also built ten 0-4-4Ts two years later). These were also the last British tank locomotives to be built with coupled wheels as large as 6ft 6in in diameter."
The latter distinction remained unchallenged, said PBSL, because a well-publicized derailment in 1927 by a Southern Railway River class 2-6-4T at Sevenoaks killed 13 people and injured another 132.
Still, the LMS 3P 4-4-2Ts headed up the former LTS suburban services for years before being replaced and relocated to other ex-MR routes. Retirements began in 1951 and ended in 1959.
Data from English Mechanic and the World of Science, No 1084 (1 January 1886), p. 370 and accessed from [],M1 on 31 January 2009. Works numbers were 2880-2891 in1880, 2969-2971 & 3018-3020 in 1881, 3217-3228 in 1884.
William Adams designed this tank engine, which became the model for several batches of LT&SE engines over the next 30 years. Their trailing axles were equipped with radial axle boxes that allowed lateral play and shrank the rigid wheelbase considerably.
Data from American Engineer and Railroad Journal - March 1893.
Thomas Whitelegg's continuation of the Adams tank engine design that first entered service in 1880. Other than differences in the number of tubes, there's very little to choose from. Works numbers were 425-430.
Data from "The History and the Locomotives of the L T & S R.," The Locomotive & Railway Carriage & Wagon Review, Vol III (January 1898), p. 4.
These were slight enlargements designed by the L T & SR's Thomas Whitelegg of the earlier Adams-designed tanks that were standard equipment on the L T & SR. Sharp, Stewart supplied the first 6, and Dubs added the other sextet. In 1900, Sharp, Stewart added 12 more, all with names, that varied only in detail and mounting a larger boiler. Reports at the time said that class "...doing good work and give every satisfaction."
These were later (1906) rebuilt with a larger boiler that measured 55 7/8" internal diameter, was pressed to 170 psi, grew to 1,099 sq ft total heating surface, and held a grate measuring 19.7 sq ft in area. Cylinders increased 1" in diameter, thus generating 17,388 lb in calculated tractive effort. The water tanks capacity also grew to 1,614 Imp gall (1,938 US gal).
Principal Dimensions by Steve Llanso of Middle Run Media | ||||
---|---|---|---|---|
Class | 79/3P | unknown | unknown | unknown |
Locobase ID | 2312 | 3214 | 5703 | 10080 |
Railroad | London, Tilbury & Southend | London, Tilbury & Southend | London, Tilbury & Southend | London, Tilbury & Southend |
Country | Great Britain | Great Britain | Great Britain | Great Britain |
Whyte | 4-4-2T | 4-4-2T | 4-4-2T | 4-4-2T |
Number in Class | 4 | 30 | 12 | |
Road Numbers | 79-82/2147-2150/41965-41968 | 1-30/2200-2229 | 31-36 | 37-48 |
Gauge | Std | Std | Std | Std |
Number Built | 4 | 30 | 12 | |
Builder | several | Sharp, Stewart | Nasmyth Wilson | several |
Year | 1909 | 1880 | 1892 | 1897 |
Valve Gear | Stephenson | Stephenson | Stephenson | Stephenson |
Locomotive Length and Weight | ||||
Driver Wheelbase (ft / m) | 8.75 / 2.67 | 8.50 / 2.59 | 8.50 / 2.59 | 8.50 / 2.59 |
Engine Wheelbase (ft / m) | 30.80 / 9.39 | 32.58 / 9.93 | 29.33 / 8.94 | 29.33 / 8.94 |
Ratio of driving wheelbase to overall engine wheelbase | 0.28 | 0.26 | 0.29 | 0.29 |
Overall Wheelbase (engine & tender) (ft / m) | 32.58 / 9.93 | |||
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 36,960 | 36,000 / 16,329 | ||
Weight on Drivers (lbs / kg) | 73,920 / 33,530 | 71,850 / 32,591 | ||
Engine Weight (lbs / kg) | 159,376 / 72,292 | 125,440 / 56,899 | 126,250 / 57,266 | 141,456 / 64,163 |
Tender Loaded Weight (lbs / kg) | ||||
Total Engine and Tender Weight (lbs / kg) | 159,376 / 72,292 | 125,440 / 56,899 | 126,250 / 57,266 | 141,456 / 64,163 |
Tender Water Capacity (gals / ML) | 2200 / 8.33 | 1560 / 5.91 | 1560 / 5.91 | 1800 / 6.82 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 2.50 / 2.30 | 2.20 / 2 | 2.20 / 2 | |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 62 / 31 | 60 / 30 | ||
Geometry Relating to Tractive Effort | ||||
Driver Diameter (in / mm) | 78 / 1981 | 73 / 1854 | 73 / 1854 | 78 / 1981 |
Boiler Pressure (psi / kPa) | 170 / 1170 | 140 / 970 | 160 / 1100 | 170 / 1170 |
High Pressure Cylinders (dia x stroke) (in / mm) | 19" x 26" / 483x660 | 17" x 26" / 432x660 | 17" x 26" / 432x660 | 18" x 26" / 457x660 |
Tractive Effort (lbs / kg) | 17,388 / 7887.07 | 12,249 / 5556.06 | 13,999 / 6349.85 | 15,606 / 7078.77 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 6.03 | 5.13 | ||
Heating Ability | ||||
Tubes (number - dia) (in / mm) | 217 - 1.625" / 41 | 200 - 1.625" / 41 | 189 - 1.625" / 41 | |
Flues (number - dia) (in / mm) | ||||
Flue/Tube length (ft / m) | 10.83 / 3.30 | 10.85 / 3.31 | ||
Firebox Area (sq ft / m2) | 119 / 11.06 | 97 / 9.01 | 97 / 9.01 | |
Grate Area (sq ft / m2) | 19.77 / 1.84 | 17.20 / 1.60 | 17 / 1.58 | 17 / 1.58 |
Evaporative Heating Surface (sq ft / m2) | 1120 / 104.05 | 1020 / 94.80 | 1011 / 93.96 | 1027 / 95.45 |
Superheating Surface (sq ft / m2) | ||||
Combined Heating Surface (sq ft / m2) | 1120 / 104.05 | 1020 / 94.80 | 1011 / 93.96 | 1027 / 95.45 |
Evaporative Heating Surface/Cylinder Volume | 131.27 | 149.33 | 148.01 | 134.11 |
Computations Relating to Power Output (More Information) | ||||
Robert LeMassena's Power Computation | 3361 | 2408 | 2720 | 2890 |
Same as above plus superheater percentage | 3361 | 2408 | 2720 | 2890 |
Same as above but substitute firebox area for grate area | 20,230 | 13,580 | 15,520 | |
Power L1 | 4442 | 3753 | 4264 | |
Power MT | 223.86 | 261.67 |