SEmG

Maunsell K/K1 class 2-6-4T

A790

The lone K Class to run for the SECR, River Avon NºA790, photographed in Southern Railway days hauling "The Southern Belle" near Merstham.

photograph: Steve Roffey collection

 
The K class 2-6-4 tank was designed by Richard Maunsell, CME of the SECR, more or less at the same time as the N Class 2-6-0. It caused a bit of a stir as the 2-6-4T was not a common design when Nº790 entered traffic in 1917, as well as being a completely new departure for an Ashford design. Due to the restrictions of the First World War no more of the class were built until 1925. The Southern Railway then ordered another twenty locos in 1925 (nine from Armstrong Whitworth & Co., ten from Brighton works and one from Ashford) and gave them all names of rivers. Nº790 was also named, as River Avon.

The motion, cylinders and boiler were all the same as on the N Class though the coupled wheels were appreciably larger at 6'. The radial and bogie wheels were the same at 3' 1". Although generally a successful class, they were prone to water shortages on the long Kent Coast routes and some crews, particularly on the Central Section, complained that they would roll heavily and unpredictably when at speed on indifferent track.

 
A795

NºA795, River Medway, also near Merstham.

photograph: Steve Roffey collection

 
The Ashford 1925-built loco, Nº890, River Frome, was built with three cylinders and designated class K1. The loco had Ho;croft conjugated valve gear similar to the N1 Class of 1923. The riding of this loco was less stable that that of the two cylinder K Class and it was twice derailed. The more serious was the second occasion when it and seven of the eleven coaches behind it were derailed at Bearsted during 1927, fortunately whilst travelling at only 35 m.p.h. and without any serious injuries being sustained.

Four days after the Bearsted accident there was a far more serious one at Dunton Green involving NºA800, River Cray when travelling at speed with a Cannon Street to Deal express. Following this serious accident trials were carried out on both the LNER and the SR which resulted in the decision to withdraw the classes and to rebuild all the locos as 2-6-0 tender types, a decision that was probably rather unfair to the 2-6-4T design as it is almost certain that the major cause of the accident was the poor state of the track rather than the locomotive design. When rebuilt the K Class locos became the U Class, with the solitary K1 becoming the first of the U1 class.

 

Technical Details
K Class

  • Introduced: 1917
  • Driving Wheel: 6 ft 0 ins
  • Pony Wheel: 3 ft 1 in
  • Radial Wheel: 3 ft 1 in
  • Length: 43 ft 6¼ ins
  • Total Weight: 82 tons 12 cwt
  • Water Capacity: 2,000 gals
  • Cylinders (2): 16 in x 28 in
  • Boiler Pressure: 200 lb sq in
  • Tractive Effort: 23,866 lb
  • Coal Capacity: 2 ton 10 cwt


K1 Class

  • Introduced: 1925
  • Driving Wheel: 6 ft 0 ins
  • Pony Wheel: 3 ft 1 in
  • Radial Wheel: 3 ft 1 in
  • Length: 43 ft 6¼ ins
  • Total Weight: 88 tons 15 cwt
  • Water Capacity: 2,000 gals
  • Cylinders (3): 16 in x 28 in
  • Boiler Pressure: 200 lb sq in
  • Tractive Effort: 25,387 lb
  • Coal Capacity: 2 ton 10 cwt
 
SECR Nº SR Nº SR Name Builder Built Rebuilt By
K Class
790 A790 River Avon Ashford Jun 1917 Jun 1928 Eastleigh
- A791 River Adur A W &Co May 1925 Jul 1928 Eastleigh
- A792 River Arun A W &Co May 1925 Jul 1928 Eastleigh
- A793 River Ouse A W &Co May 1925 Jun 1928 Eastleigh
- A794 River Rother A W &Co May 1925 Jun 1928 Eastleigh
- A795 River Medway A W &Co Jun 1925 Jun 1928 Eastleigh
- A796 River Stour A W &Co Jun 1925 Jul 1928 Eastleigh
- A797 River Mole A W &Co Jun 1925 Jun 1928 Ashford
- A798 River Wey A W &Co Jun 1925 Aug 1928 Ashford
- A799 River Test A W &Co Jun 1925 Jul 1928 Ashford
- A800 River Cray Brighton Jul 1926 Dec 1928 Ashford
- A801 River Darenth Brighton Jul 1926 Jul 1928 Ashford
- A802 River Cuckmere Brighton Aug 1926 Jul 1928 Ashford
- A803 River Itchen Brighton Aug 1926 Jun 1928 Brighton
- A804 River Tamar Brighton Sep 1926 Jun 1928 Brighton
- A805 River Camel Brighton Oct 1926 Mar 1928 Ashford
- A806 River Torridge Brighton Oct 1926 Jun 1928 Brighton
- A807 River Axe Brighton Nov 1926 Jun 1928 Brighton
- A808 River Char Brighton Nov 1926 Jul 1928 Brighton
- A809 River Dart Brighton Dec 1926 Jul 1928 Brighton
K1 Class
- A890 River Frome Ashford Dec 1925 Jun 1928 Ashford

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This page was created 28 January 2009

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