1. The Marshall Portable Boiler (049) was manufactured in Gainsborough in 1938 and was originally used as a stand-by steam generator in London. Using wood as fuel, it now provides steam at 50 psi to power all the steam engines in the museum. It is similar in design to most locomotive boilers with the smoke and hot gases passing from the firebox through fire tubes surrounded by approximately 672 gallons (3050 litres) of water in the boiler barrel. The effect can be compared to having immersion heaters 2.5 inches (64mm) in diameter 10 feet (3 metres) long.

The boiler was donated by: Kew Bridge Pumping Station Museum and has been restored by the Trust with the help of a partial grant from the PRISM foundation. (Preservation of Industrial and Scientific Materials) New fire tubes have been fitted and all ancillaries overhauled in order to bring it up to safe working order.

The large (and loud!) steam whistle (069) mounted on this boiler came from Wattstown Colliery whilst the smaller whistle (070) is from Ty Mawr Colliery. Both were donated by the National Coal Board. Well behaved visitors are sometimes allowed to try them out, but please ask the boiler attendant first!