Pendon Museum, in the village of Long Wittenham near Abingdon, Oxfordshire, recreates the idyllic rural England of the 1920s and 1930s in miniature. The Pendon Museum Trust was established in 1954 by the Australian-born artist and craftsman Roye England, who, dismayed at the destruction and modification of historic Vale of White Horse buildings, began making exact scale models of them. The museum is an independent, accredited museum (Accredited Museum No. 963, Registered Charity No. 313614) run almost entirely by volunteers and funded by visitors and its Friends.

All the model trains are hand-built to 4 mm to 1 foot scale (1:76) and run on 18 mm gauge track, a combination known as EM gauge. They portray typical scenes on the Great Western Railway of the 1920s, with operating sequences based on period timetables. Roye England ran Pendon jointly with the English model maker Guy Williams, who built fifty-seven of the museum's ninety locomotives.

The collection centres on three displays: the vast Vale Scene, the ground-floor Dartmoor Scene, and John Ahern's pioneering Madder Valley Railway. Together they trace not only 1930s rural life but also the history of scenic railway modelling itself.

Photography is welcomed throughout the museum and visitors are encouraged to share images on social media, but flash photography is not allowed. The Vale Scene rewards slow, low-angle viewing of individual vignettes such as Britchcombe Farm and Pendon Parva Junction, while the Dartmoor Scene's timber viaduct and engine shed make strong compositions. You may not photograph other people's children without their parents' or guardians' permission, and anyone wanting images for commercial use must clear it with the museum in advance.

The Vale Scene is described by the museum as probably the largest diorama anywhere based on accurately reproduced buildings, landscape and railways. Under construction since the 1950s, it depicts the Vale of White Horse as it was in the 1930s, centred on the fictional village of Pendon Parva served by a GWR main line. Every building and significant feature is an exact model of a real building from the Vale: Duck's Stores, with origins as far back as 1550, was completed in model form in 2012 and its roofs carry approximately 31,000 individually painted and weathered tiles. Locomotives modelled on the layout include GWR 2900 Class No. 2943 Hampton Court (built 1912), GWR 4000 Class No. 4050 Princess Alice (built 1914), and GWR 2251 Class No. 2253 (built 1930).

The ground-floor Dartmoor Scene, originally built in 1955 to showcase the trains being constructed for the Vale, portrays an imaginary GWR branch line on the southern edge of Dartmoor. Its focus is a model of one of Brunel's timber viaducts at Walkham in Devon, built by R. Guy Williams. The Madder Valley Railway, built by John Ahern between 1941 and 1951, is one of the most historically important model railways in the world: it pioneered the idea of setting a model railway in a believable landscape of towns, villages and countryside, and it came to Pendon after Ahern's death in 1961.

Pendon is a quiet, contemplative place rather than a hands-on attraction, and its volunteer guides are on hand to explain the models and 1930s rural life. The museum is fully air-conditioned and offers a tea room serving light refreshments, a shop selling railway and modelling books and the museum's own range of 3D-printed figures, and free wi-fi. To preserve the historic models, the Madder Valley and Dartmoor layouts are run only on a few selected days each year (marked in amber on the museum calendar), so check ahead if you want to see trains in motion. The Vale Scene occupies an upstairs gallery that is not accessible to wheelchairs or pushchairs; the ground floor, tea room and Dartmoor Scene are step-free. Families are well catered for with I-Spy style trails for ages 6 and up, and free drop-in Junior Model Making sessions for 6 to 14 year-olds on Wednesdays during school holidays.