GWR 3521 Class explained

GWR 3521 class
Powertype:Steam
Designer:William Dean
Builder:GWR Swindon Works
Builddate:1887–1889
Ordernumber:Lots 73, 76
Serialnumber:1095–1114, 1117–1136
Driverdiameter:5feet
Trailingdiameter:4feet
Wheelbase:16feet
Cylindersize:17x dia × Stroke
Operator:Great Western Railway
Fleetnumbers:3521–3540, 3541–3560

The 3521 Class were forty tank locomotives designed by William Dean to haul passenger trains on the Great Western Railway. They were introduced as locomotives in 1887, but were quickly altered to become s to improve their running. Following two serious accidents they were further altered from 1899 to run as tender locomotives, in which form the last was withdrawn in 1934.

Locomotives

0-4-2T standard gauge

The first twenty locomotives were turned out in 1887 as locomotives for services on the lines.

0-4-2ST broad gauge

In 1888 a further batch of twenty were ordered as s for the broad gauge lines in Devon and Cornwall.

0-4-4T broad gauge

3521 Class
Powertype:Steam
Driverdiameter:5feet
Trailingdiameter:3feet
Wheelbase:21feet
Notes:Only changes are shown

Due to the unsteady running of the s, the last of the order, 3560, was turned out in August 1889 as a bogie side tank. The remainder of the class were altered to a similar layout over the following two years. 3560 was slightly different at this time, having a bogie that was 6inches shorter and an overall wheelbase of 20feet, rather than the 21feet of the converted locomotives.

0-4-4T standard gauge

3521 Class
Powertype:Steam
Driverdiameter:5feet
Trailingdiameter:3feet
Wheelbase:21feet
Boiler:GWR 2301
Cylindersize:17x dia × Stroke
Operator:Great Western Railway
Operatorclass:3521 Class
Designer:William Dean
Builder:Great Western Railway

The standard gauge s were converted to s in the same manner as the broad gauge locomotives, which were all eventually converted to standard gauge. By the end of 1892 the whole class of forty locomotives was to one standard design for the first time.

4-4-0 standard gauge

All forty locomotives were rebuilt as tender locomotives between 1899 and 1902. Twenty-six locos retained their parallel domed boilers while fourteen received new Standard No 3 parallel domeless boilers (later replaced by the taper barrel version of that type).[1] [2] (Holcroft states that twenty-six received Standard No 3 boilers.)[3]

Holcroft[4] was of the opinion that the original inside and outside frames were modified whereas Le Fleming[5] was of the opinion that new inside frames would have been required. However as the modification also increased the coupled wheelbase from to, it is unlikely that much of the original framing was re-used.

Two locomotives, 3521 and 3546, were transferred to the Cambrian Railways in 1921 to replace locomotives destroyed in the Abermule accident. They were allocated Cambrian numbers 82 and 95 respectively but these were never carried, the two locomotives being returned to the Great Western Railway with their original numbers when the two railways were grouped together in 1922.

Accidents and incidents

References

Notes and References

  1. Book: Gibson . John C. . Great Western locomotive design : a critical appreciation . 1984 . 45 . David & Charles . Newton Abbot [Devon] . 0715386069.
  2. Book: le Fleming, H.M. . White . D.E. . The Locomotives of the Great Western Railway, part seven: Dean's Larger Tender Engines . October 1954 . . Kenilworth . 0-901115-18-5 . 655235293 . G45–G48 .
  3. Book: Holcroft, Harold . An Outline of Great Western Locomotive Practice 1837-1947 . 1957 . Ian Allan Ltd . 79 . Harold Holcroft . Shepperton .
  4. Book: Holcroft, Harold . An Outline of Great Western Locomotive Practice 1837-1947 . 1971 . 1957 . Ian Allan Ltd . 0-7110-0228-2 . 78 . Harold Holcroft . Shepperton .
  5. Book: le Fleming, H. M. . The Locomotives of the Great Western Railway, part seven: Dean's Larger Tender Engines. October 1954 . . 0-901115-18-5 . G45 . White . D.E. . Kenilworth .
  6. Book: Trevena, Arthur . Trains in Trouble . 1 . Atlantic Books . Redruth . 1980 . 10–11 . 0-906899-01-X.

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