LMS Hughes Crab 2-6-0 Mogul

The London Midland and Scottish Railway (LMS) Hughes Crab or Horwich Mogul is a class of mixed traffic 2-6-0 steam locomotive built between 1926 and 1932. They are noted for their appearance with large highly-angled cylinders to accommodate a restricted loading gauge.

These locomotives were referred to by loco spotters as "Crabs", although the term "Horwich mogul" was preferred by the LMS. Several authors have claimed that this refers to the resemblance to a crab's pincers of the outside cylinders and valve motion. Another suggestion is that the nickname refers to the "scuttling" motion felt on the footplate when the engine is being worked hard,[2] due largely to the inclined cylinders, producing a sensation that it is walking along the track. In some areas they also received the nickname "frothblowers" from their tendency to prime easily when the boiler was overfilled, or the feedwater contaminated

Designed by George Hughes, Chief Mechanical Engineer of the LMS, and built at the ex-L&YR works at Horwich and the ex-LNWR works at Crewe, they were put into service by his successor, Henry Fowler. The design incorporated a number of advanced features for the time such as long travel valves, compensated brake gear, a new design of tender and a new boiler, the latter based on the one fitted to Hughes' four-cylinder Baltic tank locomotives built at Horwich.

Fowler tried to have the design altered to use standard Derby components. However the design process and pre-production were sufficiently advanced to prevent the fitting of a smaller Derby pattern boiler, and the cylinders and motion also remained as designed by Hughes. The tender was replaced by a Derby standard type, which was narrower than the cab. Standard Midland Railway boiler fittings and brake equipment were also substituted, and the class became something of a hybrid design. Nevertheless they performed rather well in most circumstances and gained a strong reputation in some areas, especially in Scotland, where they became the preferred locomotive for heavy unfitted mineral work on difficult routes, even after the introduction of the Stanier mixed traffic 4-6-0s.

 

Like all Moguls, a rather unsung hero.

Why on earth the LMS built the useless ex Midland designs rather than more of these I fail to understand

 

Very facinating engines. A matter of taste of course but to me I think the cylinders are all to inclined and give it a bit odd appearance.

 

The Crabs inherited the L&Y's moderate boiler pressure policy. In order to have the desired tractive effort the cylinder diameter had to be relatively large to compensate for the lowish boiler pressure. So as the remain within the loading gauge the cylinders were steeply inclined.
Ray.

 

I have added over 55 new photos to the collection of George Hughes mogul 2-6-0 ‘Crab’ class
Including this photo of
42881 after the Settle rail crash that occurred at Langcliffe near Settle, on the 21 January 1960 in which two trains collided, killing 5 five people and injuring 8
https://tinyurl.com/y4vau7tp

Neil

 

I have the first part of new photos of Hughes ‘Crab’ mogul design
Including this new photo of
13016 Doncaster on a race special from Bradford
https://tinyurl.com/mr3yb6aa
18 new photos start here with
13006
https://tinyurl.com/ysehserd
to
13225
https://tinyurl.com/27sjadfy

Neil

 

Great photos Neil.
I didn`t know that some of the "Crab" were equipped with Caprotti valve gear.


Knut

 

Neither did i ... i knew some had Lentz valvegear

 

Replaced in 1953 with Reidinger valve gear:

https://en.wikipedia.org/wiki/LMS_Hughes_Crab#Experiments

Perhaps a valve gear expert could explain how Reidinger valve gear differs from Lentz & Caprotti gear?

 

Not an expert, but I believe it was to do with varying the cut off. The Lentz gear had a (very) limited range of cut off positions. Reidinger, who had worked at Lentz, developed a variation to the system which was infinitely variable and this was applied to the five Lentz geared Crabs. I've no idea about the differences to Caprotti gear.

 

A new build locomotive of this class fitted with Lentz valve gear and double chimney would be interesting.

 

Personally i'd like to see one built as Horwich had originally intended with a tender that matched the loco rather than the mis match of a Fowler one

 

I have the second part of new photos of Hughes ‘Crab’ mogul design
This collection features the LMS post 1933 numbering
Including this photo of
2824 Nottingham (1 of 5 locos fitted 1931 with Lentz rotary cam poppet valves. Valve gear replaced by Reidinger rotary poppet valve gear in 1953)
https://tinyurl.com/286zpd8m
new photos start here with
2705 Blackpool central 7th June 1936
https://tinyurl.com/ycaamv7x
to
2823
https://tinyurl.com/2p9yrxnm
to
2935
https://tinyurl.com/4brtebct

Neil

 

I have added over 50 new photos to the third collection of Hughes ‘Crab’ mogul design
This collection features the B.R. era
Including these photos of the 3 now preserved Crabs
42700 at Liverpool & Preston courtesy of Tony Gillett
https://tinyurl.com/2pwyh8p7
https://tinyurl.com/2p9as7ns
42765 & Black 5 45193 pass Leyland 19th August 1961 courtesy of Tony Gillett
https://tinyurl.com/3cb6akas
42859 with a loco boiler on first wagon near Tring Cutting 8th May 1954
https://tinyurl.com/yckvz2vk

Full collection over 50 new photos starts here with
42706
https://tinyurl.com/2p93srff
to 42726
https://tinyurl.com/3ukyb8x6
to 42776
https://tinyurl.com/2s3632s5
to 42841
https://tinyurl.com/3bx7n5my
to 42983
https://tinyurl.com/2p9ej3fy

Neil