James Evans, owner of our resident steam locomotive ‘Velinheli’ and founder/design coordinator of the LYD Project, has recently announced, in an article published in the Welsh Highland Railway Society’s magazine, a proposal to construct an exciting new narrow gauge steam locomotive. Unlike LYD which as a ‘replica’ had to be kept within the original leading dimensions and detailed appearance, the objective of the new project is to create a locomotive specifically for anticipated future requirements of the rebuilt Welsh Highland Railway, with particular focus on fuel efficiency, clean combustion, high reliability and low maintenance costs.
Whilst the NGG16 Garratts currently in use on the WHR are more than adequate for current operations, and indeed the Welsh Highland revival would not have taken place without their availability, they are themselves museum pieces and expensive to rebuild, operate and maintain. A ‘built for purpose’ design would incorporate the best modern materials and technology, so that maximum performance could be achieved from a relatively small and simple locomotive, which would consequently be financially viable to build, and run in service. This would still be a substantial machine: an 0-6-4-0T. weighing 37.5 tons in working order.
The key concept is to combine all the best and very different features of the WHR Garratts and the Fairlie locomotives of the sister Ffestiniog Railway, involving the removal of all ‘dead weight’ (carrying axles and separate boiler cradle), with all wheels driven and transmitting maximum tractive effort. The main features from each design are as follows:
Main features from the Fairlie design:
- All wheels driving (no dead weight)
- Simple bogie articulation (coach-like ride)
- Boiler/tank assembly forms mainframe (weight saving)
- Clear sight lines for crew (safety)
- Good bore/stroke ratio (efficiency)
- Separate regulators (slipping control)
Main Features from the Garratt design:
- Single ended, short, large diameter boiler (free steaming, cheaper to make/maintain)
- Walk through cab (crew comfort and safety)
- Outside frames to power bogies (stability, reduced axle box stresses)
- Outside valve gear and springs (serviceability)
- Piston valves (reduced friction)
- Reasonable superheat (fuel and water saving, without increased maintenance)
- Compensated suspension (reduced track damage).
The external appearance of the ‘Fairratt’ would be traditional and to the highest standards of finish.
Although the project is not currently backed by the WHR, which is currently focused on fundraising to finish the railway’s infrastructure and provide more passenger carriages, James has been very pleased to receive considerable encouragement and advice from several leading steam locomotive engineers, who agree that steam’s unique features combined with modern design should ensure that it has an exciting future.