Rapido OO Andrew Barclay Fireless 0-4-0

As the railways established themselves as a reliable method to transport goods one problem came to the forefront – Fire.
Steam locos fundamentally need a heat source created from some form of fire to turn water into steam. However, this fire, alongside sparks emitted from the chimney, caused great concern in environments where munitions, fuel or other flammable materials were being moved or stored. What was needed was a locomotive that didn't have a naked flame on board.

As these locations usually had a stationary steam boiler, often supplying steam at high pressure to provide heat for processing materials and run factory machinery one simple solution was to use this steam supply to run the a locomotive by charging the 'boiler' from the factory steam supply. Such a locomotive would be able to run for a period of time without needing a fire to generate steam and was known as a fireless locomotive. It quickly became obvious that, not needing water tanks, a much larger 'boiler' could be carried and accommodate extra lagging to reduce heat loss, thus extending the time between steam charges. As no actual heating of the water was done on the locomotive this large boiler-like vessel is called a steam reservoir.
At the start of a shift this reservoir would be charged at the best possible pressure, preferably several hundred lbs psi, resulting in a mix of water and steam in the reservoir. Work would then commence, normally using steam at a much reduced pressure, often 60-100 lbs psi, with larger cylinders being fitted to produce a tractive effort similar to a small conventional locomotive.
As the pressure in the reservoir begins to fall the water in the reservoir turns to steam and often these fireless locomotives would be able to work over 4 hours between charges, usually being recharged as they crew took their break.

In its' refined form the result is a design that appears to have a very large boiler, but lacks other features which people associate with traditional steam locomotives, such as a firebox, smokebox and chimney. The lack of the fire and chimney also allows the cylinders to be mounted at the rear, which improves efficiency as steam pipes are much shorter with the drivers controls, clylinders and steam exhaust at the rear of the cab all grouped closely together and offers a better weight distribution between the driven axles.

Almost all the British locomotive builders built or were able to offer a fireless locomotive design but the most prolific builder of the type was Andrew Barclay & Co. Ltd of Kilmarnock. An impressive 114 were built between 1913 and 1961 to a number of standard basic designs, often customised for customer requirements. Rapido Trains have selected one of the most numerous of the Barclay designs, the 'Caledonia'. This was a 'stock' design, Barclay's keeping a semi-completed locomotive or parts ready for assembly on hand, allowing an order for a base locomotive or with standard factory options only to be supplied very quickly.

In service the fireless locomotive was as robust as a conventional steam locomotive but suffered much less from wear and needed much less maintenance. Even the steam reservoir is a much less complex pressure vessel than a steam boiler and, with the 'fuel' on an industrial site with high-pressure steam readily available being effectively free, a fireless was often more economical than a diesel shunter. While coal fired locomotives had generally been replaced by the early 1970s many petro-chemical plants retained their fireless steam locomotives with several examples still hard at work in the 1980s. While a number of fireless engines have been preserved it is unusual to see one in operation as heritage railways generally do not have a suitable steam source available and the locomotives' low power precluding revenue-earning passenger train haulage. At least one has been run however, charged with steam from another conventional industrial shunting engine.