I'd not previously fired a 'B1', so I was pleased to be invited to fire on the second round trip of the day. Since that trip passed off without problem, I also fired the third round trip.
The Great Northern Firedoor
People are sometimes put off by the distinctive Great Northern 'Trap Door' firedoor, but I was used to this type of firedoor from working on other locomotives like 'Flying Scotsman' and 'Sir Nigel Gresley'. The firehole is oval, covered by a large, oval, dished, cast door. This door is hinged on the left and held closed by a vertical sliding catch on the right. The door has a smaller, oval aperture which is covered by a flap (the 'trap door') carried on a horizontal pivot. The pivot is positioned just above the centreline of the door aperture. When the flap is vertical (as shown in the photograph), the firedoor is closed, with only a minimum of 'top air' admitted to the firebox around the edge of the flap. The vertical bar in front of the firedoor is hinged at the top and has a sawtooth profile on the inside. The sawtooth forms a ratchet, allowing the flap to be opened to a number of different angles.
To increase the amount of 'top air', the fireman simply pushes the lower part of the flap with the shovel blade. The flap pivots and the hinged ratchet bar retains the flap at the desired angle. This is both simple and effective.
To fire, the fireman pushes the lower part of the flap with the shovel blade until the ratchet bar retains the flap in a horizontal position. Reasonable accuracy is needed to slide the shovel through the aperture underneath the flap and it's essential not to overload the shovel.
Left Hand - Right HandWith left-hand drive locomotives like this, the fireman should be on the right of the footplate, so this tends to favour a fireman who is naturally left-handed. In the old days, fireman tended to learn to be ambidextrous, so as to keep out of the driver's way whether locomotives were left- or right-hand drive but in preservation, drivers tend to be more tolerant of fireman working from the wrong side. I'm naturally left-handed, so the 'B1' suits me. I can fire a short firebox left- or right-handed, but to get down the front of a longer box, I really prefer to be standing on the right.
Stance
Stance is important - even in preservation, the footplate can become a little 'lively' on the road so the fireman should choose a firing position that can be retained when the engine's in motion. The fireman should avoid being a 'dancer', moving about during firing. I was taught to 'be a tree' and place your feet so that both the coal supply and the firebox can be reached just by twisting the upper part of the body. On the 'B1', I found a position just to the right of the firehole, turned slightly towards the tender suited me.
Height above the Footplate
The other crucial factors are the height of the shovelling plate in the tender and the height of the firehole above the footplate. These heights vary enormously from class to class. Great Western tender engines have no raised shovelling plate - you're shovelling the coal from the floor of the coal space at footplate level. The 'B1' is similar with a very low shovelling plate (see the photograph at the top of this post). Locomotives like this probably favour shorter fireman. It's certainly desirable to be able to bend down without problems. On fairly modern designs of tender (like the Stanier) a raised shovelling plate is more common, so that the coal is presented at a level considered more convenient. The fireholes on Great Western types and on the 'B1' are set fairly low on the boiler backhead and this works fairly well with a low shovelling plate - too much difference in height between shovelling plate and firehole can make accurate firing harder. You really need to 'calibrate' your swing so that the shovel blade arrives at the firehole at the right level without looking or without consciously thinking about it. This is where practice is essential.
Firing
So how did I fire it? Well, with any unfamiliar engine, you have to make an educated guess about what's needed and be prepared to modify your technique if you don't get the right results. As departure time approached,I decided on a small firing to get the boiler pressure up to near the blowing-off point. You want to give your driver confidence that he's got full pressure for starting away. Water level in the gauge glass was about an inch and a half below the top, so I knew that if she 'made' faster than I expected, I could put the injector on to prevent blowing off. I tried a light firing of six shovelfulls, two in the back corners, two halfway down the box and two towards the front. Each pair was placed one on the left, one on the right and then the trap door was closed. I was gratified to see the pressure come up quite quickly and hover just below the 'red line'. Checking the chimney, the exhaust darkened as I fired, but quickly turned an acceptable grey. Since the platform was my side, I kept looking out for the guard's 'rightaway'. When I saw the 'tip' I shouted "Rightaway!" to the driver and, at the same time, gave an acknowledgement by hand to the guard.
I try to avoid the temptation to fire again as the train starts away. Firstly, a lot more air is being drawn through the firebox with the regulator open and it takes a while for the temperature of the firebed to be raised. Adding coal too early just cools the fire and makes it more likely that the boiler pressure will fall. Secondly, the period as the coaches are being drawn out of the platform is more dangerous. The slow speed may encourage people to attempt to get off or get on. Station staff may spot something unsafe and they can only alert the footplate crew if somebody is looking back. A glance at the boiler pressure gauge showed that the pressure was holding up.
Once the train was clear of the platform, I fired another six, as before. As long as the exhaust from the chimney is grey, it indicates that volatiles are still being driven out of the coal. Once the exhaust becomes pale grey, it's time to fire again, unless you know the driver is about to close the regulator and reduce his consumption of steam. This is why a fireman needs to know both the route and the driving technique adopted by each driver.
(More follows)
This picture shows Jan looking out for the guard's 'rightaway' from Shenton.
