A History of 
Class B7 "PUG" 0-4-0
The Lancashire and Yorkshire Railway was formed in 1847 out of the Leeds and Manchester Railway and, over the following 76 years grew to cover no less than 590 route miles and 309 stations or halts.
  The Railway became affectionately known as the ‘Lanky’ and very quickly developed a huge amount of business moving raw materials and other goods throughout Lancashire and over the Pennines into Yorkshire. 
No. 51206 - Photo. courtesy of Liverpool Locomotive Preservation Group.

In 1922 the L&YR joined with the LNWR Company, but both were swallowed up into the London, Midland  and  Scottish Railway at the 1923 Pre-Grouping.
The L&YR was always self-sufficient for locomotives and rolling stock and built its own railway works in 1884 at Horwich. By 1892 Horwich had become a railway town and the works had grown to include five erecting shops, iron and steel foundries, signal and point shops, a chain foundry and its own gas and electricity plants.By 1894 no less than 300 new locomotives had been built, sometimes at the rate of two per week.
Included in this impressive production were the B7 class 0-4-0 saddle tanks, or “pugs” as they became known. Introduced in 1891 and designed by John Aspinall, a total of 57 such locos were built at Horwich between 1891 and 1920. They were built in six batches under Aspinall, between 1891-99 and George Hughes between 1904 and 1910. Hughes had become CME of the L&YR in 1904.
With a total weight of only 21.25 tons, wheels of 3’0” diameter and a wheelbase of only 5’9” the Pug’s prime purpose was shunting duties on docksides and yards where their short wheelbase allowed them to negotiate any sidings or tight radius curved track. The Pugs were given running numbers in the L&YR build sequence, so preserved Pug number 68 later became LMS number 11218 and BR number 51218.
Of the 57 Pugs built, two were withdrawn in 1926 having never received LMS numbers, whilst a further seven were sold by the LMS to private owners between 1931 and 1937. Twenty three survived to work for British Railways with the last of the class being withdrawn in 1964. 
The Pugs had some unusual design features including dumb buffers, open cabs, protective covers over the slide bars and crossheads and a swivelling smoke hood to deflect the blast from the chimneys on some of the locos which operated in warehouses or areas with low headrooms.
Two Pugs survive today - Number 51218 had a varied working life ending up shedded at Preston by 1950, followed by spells at Monument Lane, Crewe South, Bank Hall, Widnes, Bristol Barrow Road, Swansea East Dock and Neath, from where she was withdrawn in 1964. 51218 went straight in to preservation and arrived at Haworth, on the KWVR in 1965 - their first preserved steam loco. Retubed in 1974 for the Stockton and Darlington parade, 51218 celebrated her 75th anniversary in steam in1976. Thereafter the loco fell into disuse. An appeal was launched in 1996 to overhaul the loco in time for her centenary in 2001. In fact, this appeal was so successful that the loco was overhauled by contractors and returned to steam in 1997. The loco has since operated on the KWVR, the East Lancs Railway, Southport Steam Centre, Cheddleton, Bristol Harbour, and the Middleton Railway. 51218 regularly runs on the KWVR, where she has made a nice niche as “Percy” from the “Thomas” stories. 51218 has been invited to attend the Shildon event in August 2000.
The other survivor, number 19, has had a very different life. Built in 1910, she became LMS number 11243, but was sold in 1931 to John Mowlem for use on a major contract at Southampton Docks where she was named ‘Bassett’. Four years later she was moved to London, was re-named ‘Prince’ and operated at the Charlton works of United Glass Bottle Manufacturers Ltd, whose site is now occupied by the Millennium Dome. Number 19 came into preservation in the late 1960s, being purchased by the L&YR Society at Haworth. She has been loaned as a static exhibit to Southport Steam Centre and is now on their new site at Preston Docks.