Across the railway network, and particularly on some of the light railways which sprang to life after the Light Railways Act 1896,  there were a number of unusual locomotives and railcars.
One of these was ‘Gazelle’ which was fabricated by Dodman’s in King’s Lynn.  Gazelle was eventually used on the Shropshire and Montgomeryshire Light Railway and remained there until closure of that line before being relocated as a static display. The Railway World Annual of 1981 has a picture of Gazelle at Longmoor Camp in June 1953, © R. E. Vincent.  Ultimately, Gazelle was moved to the Colonel Stephens Museum at Tenterden. Colonel Stephens made use of a wide range of locomotives, railcars and carriages to keep the costs of running his network of light railways to an absolute minimum. He would mix-and-match, make-do-and-mend until he was satisfied that a particular solution was appropriate for one of his lines. 
Similar experiments were undertaken on other light railways. For example, the Brill Tramway made use of a version of a road-running steam engine but of a redesign which enabled it to operate on rails. I came across the small Aveling and Porter locomotive while reading ‘British Independent Light Railways’ by John Scott-Morgan. 
￼Old Chainey is a chain and flywheel-driven loco built in 1872, for use on the tramway between Quainton Road and Brill. It was not very successful, especially if loads were heavy. It lasted in service on the Tramway until 1895 when it was sold for use at Nether Heyford Brickworks in Northamptonshire, where it continued working until the Second World War. Indeed the Industrial Railway Society provides a photograph of this Locomotive a (see below) at Nether Heyford in 1936. 
It is now a static exhibit. It was placed, first at the London Transport Museum and then on long-term loan from the London Transport Museum to the Buckinghamshire Railway Centre. 
The locomotive was Aveling and Porter No. 807 (and became Wotton Tramway No. 1). It was nicknamed “Old Chainey” because it was noisy. It had a flywheel which drove a large-linked chain which in turn drove the wheels. 
It was the first steam locomotive used on the Wotton Tramway. 
The lightly laid track on the Tramway with longitudinal sleepers limited them to about 9 tons  and necessitated the use the lightest locomotives possible. [8: p13] No. 807 was the first of two locomotives converted for use on the Tramway. They cost £398 each. [8: p13] No. 807 was delivered to the Tramway in January 1872. The second loco was delivered in September of the same year. [8: p18][10: p29]
Although the two engines had a top speed of 8 miles per hour, they averaged 4 mph between Brill and Quainton Road. [8: p18]
As we have already noted, No. 807 was sold for industrial use. It appears in the adjacent image at Nether Heyford Brickworks on 11th April 1936, © G. Alliez. This image accompanies an article from ‘The Engineer’ reproduced by the Industrial Railway Society. 
That article, discussing a series of tramway locomotives produced by Aveling & Porter, appeared first in the Industrial Railway Record, Volume No. 48. It talks of No. 807 in the following terms: …
Aveling & Porter 807 of 1872 is shown above “at the Nether Heyford Brickworks (Northamptonshire) of Henry Martin Ltd. The engine was one of a pair which were obtained by the Blisworth & Stowe Brick & Tile Co Ltd – Martin’s predecessors – from the Oxford & Aylesbury Tramroad Co in 1894. Originally supplied in January 1872 to the Duke of Buckingham (for the Oxford & Aylesbury Tramroad), 807 had a single cylinder (7¾in by 10in) and was carried on wheels of 3ft 0in diameter. … The brickworks closed in 1940 but was used as an ammunition store by the War Department. Happily, 807 survived the War, being stored until March 1951. It was then secured by the Industrial Locomotive Society, and is now on display at the Museum of British Transport, Clapham.” 
As noted above, it can now be found at the Buckingham Railway.
1. https://en.m.wikipedia.org/wiki/Light_Railways_Act_1896, accessed on 1st January 2020.
3. https://www.tripadvisor.co.za/LocationPhotoDirectLink-g503919-d261283-i102801148-Kent_East_Sussex_Railway-Tenterden_Kent_England.html, accessed on 1st January 2020.
6. https://en.m.wikipedia.org/wiki/Brill_Tramway, accessed on 1st January 2020.
7. Vic Mitchell & Keith Smith; Aylesbury to Rugby; Middleton Press, Midhurst, 2006.
8. Ian Melton, “From Quainton to Brill: A history of the Wotton Tramway”; R. J., Greenaway (ed.). Underground, Hemel Hempstead: The London Underground Railway Society, 1984.
9. Bill Simpson; A History of the Metropolitan Railway; Lamplight Publications, Whitney, Oxon, 2005.
10. Bill Simpson; The Brill Tramway. Oxford Publishing, Poole, 1985.
11. The Industrial Railway Record httpsVolume No. 48, p34-38; https://www.irsociety.co.uk/Archives/48/AP%20Locos.htm, accessed on 1st January 2020.
12. https://images.app.goo.gl/T3ytjyL6xWxAmwqKA, accessed on 1st January 2020.
13. Railway Work Annual, Ian Allan, Shepperton, Surrey, 1981, p87.