Just like roads, railways have speed limits. The maximum speed on the Welshpool and Llanfair Light Railway is 15mph, although the speed limit is 5mph at road crossings, facing points, and within the stations. The difference between cars and steam engines though, is that a steam engine doesn't have a speedometer. This means that you have to guess how fast you are traveling. The instructions I was sent before the driver experience suggest that 5mph is a smart walking pace, 10mph is jogging and 15mph is a sprint. While this sounds helpful it is difficult, especially for someone like me who doesn't drive a car, to figure out exactly how fast you are traveling.
As I said before, slowing a steam engine down is much harder then starting it moving. Add to this the changing slope of the railway and it can be quite easy to suddenly find your self moving quite fast. According to my instructor for the afternoon I definitely hit 20mph on one section of the line when I was surprised by a slight dip. Obviously if you know the line well then you can preempt a slope and slow the engine accordingly to avoid going too fast. Unfortunately I didn't know the line that well.
The Welshpool and Llanfair Light Railway claims to be "Britain's steepest adhesion worked railway" because of Golfa Bank. Golfa Bank is towards the end of the outward journey as you drop down towards Welshpool. The gradient profile of the line records the bank as 1 in 29. As a comparison most mainline railways in the UK have a gradient of 1 in 40 or less, so the Golfa Bank is most definitely steep.
So if we combine my inability to determine how fast we were traveling and my lack of experience of the railway then clearly disaster couldn't be far away.
We had just rounded a corner and in front of us there was a slight rise and a 10mph speed limit sign when my instructor said "you have to be doing 10mph when you pass the sign otherwise you will never make the bank". Given the slight rise and the fact that I though I was doing less than 10mph I slowly started to open the regulator...
It took a few seconds and the fireman was actually the first to react. He dived across the cab and pushed the vacuum brake on full slowing the engine to a crawl (but surprisingly not to a full stop). Of course I had been going at almost 10mph and the curve in the line was hiding the fact that we were about to descend Golfa Bank. A quick conversation ensued where it became clear that not knowing the line I'd misunderstood the instruction, but at least we were all alive to tell the tale!
Descending Golfa Bank is actually quite demanding. The weight of the engine and carriages is more than enough to propel it forward down the slope. As the driver you have to be constantly slowing the engine down by applying the brake. The line isn't straight, so this is really important, as the last thing you want to do is end up jumping the tracks or rolling over! Fortunately after the little health scare we made it down the bank into Raven Square station in Welshpool without any further problems.