S15 847

847 is the Society's largest and most powerful loco. It was the last loco built of its class and the very last 4-6-0 built by the Southern Railway.
Maunsell's S15 was a modification of Urie's design for a heavy goods loco. Maunsell's design included a boiler working to a higher pressure, improved draughting arrangements, and in 847's case a flat sided, more modern looking 5,000 gallon bogie tender.

Built at Eastleigh, 847 entered traffic in December 1936, and spent a number of weeks on running in turns from Eastleigh. It was first allocated to Exmouth Junction shed, where it remained until being re-allocated to Salisbury in 1951. In July 1959 it was re-allocated to Redhill shed where it joined S15's 833-836 for use on the Redhill-Reading line. A few months after arriving at Redhill it was allocated a six wheel tender (number 914) that had previously been attached to 30797 'Sir Blamor De Ganis', to facilitate turning on the shorter turntables present on the Redhill-Reading line. A further move to Feltham shed followed in June 1963, but by then its days were numbered and it was withdrawn in January 1964.

Sold to Woodhams Brothers scrapyard at Barry, it was taken to Barry in company with 30499, 30506 and 30841, all now preserved.
The 847 Locomotive Preservation Fund was formed in 1976 with the aim of purchasing in restoring 847. The fund merged with the Maunsell Locomotive Society and the loco was purchased for £9,750 including VAT and transported to the Bluebell Railway in October 1978. A Urie eight wheel bogie tender, no 3225 (that had been coupled to S15 828) was purchased to accompany the loco.

The restoration of 847 commenced in early 1984, following completion of 541. The loco and tender were fully stripped down and overhauled. Three coupling rods were purchased from another society. One new coupling rod forging was purchased and machined. New cylinder liners were purchased and fitted. The tender tank was badly corroded in places and a major rebuild undertaken which has altered the appearance to that of the Maunsell flat sided design with which 847 was first attached. 847 returned to steam on 12th November 1992, after works costing a very modest £40,000.

The loco ran for nearly 5 years until 6th September 1997, due to the expiry of its boiler certificate. However after covering over 30,000 miles other repairs were also required, including re-profiling the tyres.

The next overhaul of 847 started in 2008, following completion of the major restoration of U class 1638. The boiler underwent replacement of all tubes, flues and elements. All stays below running plate level were replaced – as were all the crownstays – a complex and difficult job, in a very confined space. The loco returned to traffic in 2013 and once again has proved to be reliable and powerful addition to the Bluebell's loco fleet. Its 6F power classification has proved of use now that Bluebell is connected to the national network. On a couple of occasions it has hauled 12 coach charter trains from Sheffield Park – up the line to East Grinstead, with ease and style. Although 847 has over two years left on its ten year boiler certificate, its tyres are showing signs of wear and it may need to come out of service before the boiler certificate expires.