The passengers told the guard and the driver that Joan was a bad engine. At certain speeds the carriages suffered a nasty backwards and forwards surging motion that made then spill their tea, fizzy drinks and ice creams. It didn’t happen when The Earl or Countess pulled the train so it must be all Joan’s fault.
So back in May this year Joan was steamed up for a series of test runs to try and ascertain what what causing this phenomenon. After a few trips up and down the line, punctuated by stops to adjust the tension in the loco’s draw springs, the finger of suspicion was pointing towards the setting of the slide valves.
Joan was built in 1927 by Kerr Stuart & Co of Stoke -on – Trent and spent her commercial working life in the Caribbean island of Antigua shunting train loads of sugar cane around the mill yard. She was acquired by the Welshpool & Llanfair Light Railway in 1971 and proved to be a useful locomotive on lighter trains.
In the 1980s she became Thomas The Tank Engine and the splendid Midland Railway red livery disappeared under a coat of bright blue paint. Inevitably the boiler became due for heavy repairs and Joan/Thomas became a static exhibit first at the end of the Coal Road and later alongside the Long Shed. Restoration began in 2006 and Joan re-entered service at the 2011 Gala.
Getting things right was not a quick task and involved adjusting the valve settings including ensuring that the valves would lift off the port faces when the loco was coasting to alleviate any back pressure in the cylinders.
She was rostered to work the 11:10 train on 12th August and I was briefed to keep a careful watch for any sign of the surging. Our train consisted of four Zillertalbahn type carriages which was an appropriate load; enough to make the loco work but not too much should we get caught in a shower of rain on Golfa bank.
After setting off from Llanfair and trundling out of the station and past Tanllan carriage shed we could begin to accelerate up to the line speed of 15mph. Going down past the old water tower it felt like we were going like the clappers. Joan has got smaller wheels than The Earl & Countess and so the number of exhaust beats per second is higher. For the same number of ‘chuffs per second’ a Beyer Peacock would be doing almost 19mph. The long overhang at the cab end also tends to accentuate any dips in the track. All in all when running cab first the crew get a lively ride.
By not notching up too early when under steam and avoiding coasting with the reverser notched up any surging on the way out to Castle Caereinion was minimal. While waiting for the trainee fireman to rejoin the train a quick conversation with the guard and some passengers in the rear coach confirmed my observations. The second part of the journey including the long descent of the Golfa Bank was also surge free and we rolled into Raven Square Station spot on time.
After running round and making up the fire we set off up the hill. It was now possible to watch the coupling between the loco and the first carriage. As expected there was a good half inch gap between the buffer heads and some rhythmic backwards and forwards motion. A brief conversation with the passengers on the front balcony confirmed that the ride quality was good. All was well up hill and down dale until we crossed the Banwy Bridge, and plodded round the corner to Heniarth. The speed limit on this short section is 10mph and Joan was bit tetchy but not to the point where the ride was uncomfortable.. Things improved as we slowed for the level crossing and did not reappear as we speeded up on the long straight towards the mill.
At Llanfair we were soon met by an anxious looking Workshop Foreman. We were able to re-assure him that once again Joan was a good little engine and deserved to be used each day we were running the four train service.
For further information and pictures about the railways and sugar cane industry in Antigua have a look at the links below. Please note that the content is not mine or under my control