Wylam Dilly Mysteries Solved

This photo is reputed to show Wylam Dilly, after moving to Craghead Colliery c1870,
accompanied (in top hats) by two of William Hedley's four sons

Wylam Dilly was built as a flangeless 5' gauge loco, but is known to have undergone several adaptations, eg to 8 wheels, flanged wheels, & as the power unit of a tug boat.   The mysteries were:

1.  Was Wylam waggonway relaid to standard gauge before Wylam Dilly left?

2.  Had Wylam Dilly been rebuilt to standard gauge?

3.  What gauge was in use at Craghead Colliery?

Both Wylam Dilly & Puffing Billy were out of use at Wylam in 1862, when Puffing Billy was donated to London's Science Museum.

Wylam Dilly has been with the National Museum of Scotland (NMS) in Edinburgh since its donation in 1882.   So if I found its current gauge, the questions could be answered.   Unfortunately, the gallery containing the loco has been under refurbishment & inaccessible for several years.   Curators did not know the gauge.  The gallery reopened in July .....

Wylam Dilly in the NMS on 5 August .....

..... in the same place as it has been for several years - refurbishment has gone on around
(Dolly the sheep is stuffed at far right)

The distance between the rails is approx 5 feet, so the loco was not converted to standard gauge,
so Wylam waggonway was 5' gauge in 1862, & Craghead colliery used 5' gauge c1870

The Tanfield Waggonway used 4' gauge until the late 1830s.   The implication is that waggonways in the area used their own historic gauges into Victorian times, & were only standardized when the lines were modernized & connected to the wider rail network.

The loco has a gear wheel on a central shaft driven by the pistons & cranks; this gear wheel
drives gear wheels on either side, which drive half size gear wheels on the axles. 

A view of the flue side

See the TR blog post for 29 December 2015 for more about Hedley & Wylam.

A very interesting 19th century descriptive account is available in a Heddon History Society blog post.

Similar questions relate to Wylam's Puffing Billy, which is in the Science Museum, South Kensington.    Because it went out of use at Wylam at the same time as Wylam Dilly, it is likely to be 5' gauge.   So the replica of Puffing Billy at Beamish is inaccurate by being standard gauge.   However, early locos would have many different gauges, so Beamish is doing its best in an awkward situation.   Does anyone know any more?