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Cymdeithas Rheilffordd Ffestiniog


Musical Bogies Part II

01 January 2014

Traditional Fairlie lineup

As a continuation of the Fairlie bogie story from Musical Bogies I, the single fairlie reproduction/replica/rebuild (depending on your stance on these things – the original reverser lever and Salter safety valve casing were used) Taliesin entered traffic in May 1999.

The mythical stories of the superb ride of a single fairlie turned out to be absolutely true and so did other parts – a single fairlie is not quite half the power of a double fairlie and also has limitations on the traction available. This has not hindered it from becoming a useful member of the fleet, taking 6 carrs or double heading as its staple diet. The comfort factor of the loco from its smooth riding and spacious cab make for an attractive proposition for crews.

Taliesin nearing completion in 1999

Taliesin has a regular shaped boiler and a similar tube layout to the David Lloyd George, including four superheater flues. Combined with the higher (than the Earl and Merddin) boiler pressure of 175 psi this results in a free steaming loco but does result in a heavy load on the valves and valve gear. Taliesin was built as an oil burner but readily convertible to coal. This occurred for the last time in Autumn 2005 as the ever-increasing cost of oil led to the decision to expand the use of coal throughout the operating fleet – Taliesin was the ideal test bed, with space for training and its forgiving steaming. A quick retube in the Summer of 2009 and external inspection by Spring 2010 saw it certified for another ten years of use.

Meanwhile, Merddin Emrys lay out of use (with its bogies putting in large mileages each year under the Earl) until in 2000 the boiler was taken to Israel Newton’s workshops in Bradford for new throatplates to be fitted, new longitudinal stays (to counter the flexing mentioned in the earlier article) and a full retube, funded by the Ffestiniog Railway Society. The rebuilt boiler returned in December 2001 and, following some routine caulking by Gordon Newton, reassembly commenced.

Corrosion on the well tank of Merddin

Reassembly hit a bit of a snag in the Autumn of 2003 during preparation for painting as the tanks were discovered to be in considerably worse condition than anyone could have expected – it was more of a body blow to those involved really. Seizing the opportunity a design was put together for one piece side and well tanks in replacement of the individual side tanks and well; these would have integrated oil tanks, rather than lift out tanks.

Thus it was hoped to eradicate the perpetual ‘sag’ that Merddin displayed following the 1988 rebuild until withdrawal. After a lot of design work and preparation an attack by staff and volunteers over Christmas that year resulted in the completion of a pair of tanks for Merddin and a pair for the Earl. The erection of the tanks on Merddin caused further knock on effects as Merddin was now straighter than it had been for years, meaning there was a lot of work to refit the cab and all other parts. The effect was noticeable though and retained the good looks of Merddin.

New tanks for Merddin under construction

The existence of parts for a new bogie together with the attraction, ability and opportunity to see three double engines in service, combined with FRS funding, conspired to create a plan to build a pair for Merddin Emrys to re-enter traffic without withdrawing the Earl. The project took just three years in which one set of wheels were cast, two sets of tyres acquired, another set of frame plates and further motion constructed. Casting problems were found with one of the steamchests and cylinder sets in stock, resulting in a repair to the pattern and new castings being made (the steamchest casting is notoriously difficult due to the number of core boxes required in the cast), along with two cylinders.

Nearly complete TE bogie at Minffordd

Merddin was united with the new bogies in May 2005 in time for the 50th anniversary of the preservation of the railway, coinciding with the visit of Livingston Thompson for the first time since going on display in York in 1989. The bottom end bogie was only just a runner, having coupling rods only fitted and no pistons. Merddin was, however, able to make appearances at Porthmadog and join in the line up of five Fairlies, although the strong evening backlighting made it difficult to take in the full picture.

A return to the works and further work during the month saw the bottom end bogie complete save for draincocks and final lubrication work, but sufficient to pilot the Earl on the Society AGM special as far as Minffordd. After various teething troubles, Merddin settled into traffic during the summer of 2005, albeit with fairly heavy fuel consumption.

Three Double Fairlies - Merddin ready to pilot the AGM train Merddin Emrys in unlined black

Following the return to availability of the DLG in late September of that year, Merddin was taken to the carriage shed for a concentrated repaint of the locomotive into the splendid lined Victorian maroon livery, similar to that carried previously. With LT present, the magical line up of Victorian locos was possible at Porthmadog on the Sunday morning.

Merddin Emrys repainted

Throughout all this the David Lloyd George has put up considerable mileages whilst undergoing regular maintenance to the bogies. It is fair to say that the work required increases each time with parts of the frames becoming brittle and wearing excessively over time. The superstructure saw a quick retube undertaken in 2003 following its requisite ten years in nearly constant service.

The virtue of having three double fairlies available was vindicated by the left field hit in April 2008 of leaks from Merddin’s boiler – rivets that attach the domes to the boiler barrel were found to be leaking necessitating an extensive exercise of dismantling and removal of the domes, prior to an agreed repair of replacement of the rivets with bolts.

Returning to traffic again in August 2008 Merddin’s performance has been consistent and provided a good base on which to do scientific testing of the draughting arrangements and valve settings. This involved setting up measurement gear on the TE bogie and smokebox and should be useful in evaluating comparative performance with future developments.

Domes removed from Merddin Laptop showing results
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