The Science of a Lost Art

19 October 2022

There are a number of skills that were once commonplace but are now practiced by very few. Sailing a tall ship is one of them. Firing a steam locomotive is another. When we were open, I’d show people around the Countess of Dufferin’s cab and I’d talk about the science and the art of firing a steamer.

I was just a teenager in 1974 when I spent a day in the cab of the Prairie Dog Central courtesy of Paul Newsome and the late Neil Pow. Neil pulled the throttle, Engine Number 3 hissed and put her weight into the train. The first blast of exhaust steam shot out the stack and the resulting chuff felt like a thump in the chest. She started chuffing at a slow walking pace and the coaches followed along.

Paul opened the firebox door for a few seconds and every time Number 3 chuffed a block of flame would leap out of the coal bed. At that moment I knew Number 3 was alive and I was watching her heart beat. What I learned over the next few hours was how Paul fed both the fire and the boiler to provide the steam Neil needed to keep the train moving. I learned both the science and the art of firing.

Firing 101 starts with a boiler, a container filled with water. The firebox sits at one end and the smokebox, with the stack, at the other. They’re connected through a series of tubes that carry the hot gases from the fire through the boiler to the smoke box. The gases heat the surrounding water to make the steam. The steam, also a hot gas, develops pressure and it’s this pressurized steam that Neil fed into the cylinders to push the pistons that drive the wheels and ultimately move the train.

As Neil used the steam it was up to Paul to make more and this requires three pieces of information: the state of the fire, the water level in the boiler and the steam pressure. As Neil fed more steam into the cylinders the water level dropped.

“Gord,” Paul said. “Put your hand on this lever, this is the injector and it forces water into the boiler and that brings the level back up where we want it.”

Paul pulled the injector from the top and I felt the water rushing through the pipe from the tender at the back and into the boiler.

“It should click at the bottom.” he told me and it did. We watched as the level climbed up the water glass over the firebox door. There was a small tap under the lever for adjusting the spray as the water entered the boiler. On a big mainline steamer the injector would be on all the time and the fireman would adjust the spray to keep the water level constant.

As we fed in the cold water we watched the pressure gauge and saw the pressure drop. Basic physics, a drop in temperature means a drop in pressure. Since we need that pressure to keep the train moving we had to bring the temperature back up. Time to feed the beast.

“Open up that door and throw some coal onto that fire.” Paul said. “Right side, left side, back and front. Keep it banked at the sides and thin in middle. Bang the scoop on the opening to spread the coal as you shovel it in. Look for dark spots, that’s where your old coal is spent.”

I opened the firebox door and was greeted with a wall of flame. Number 3 was hauling and she was hungry. I could see a few dark spots on the coal bed where the spent fuel yielded no fire.

BANG! Right side. BANG! Left side, front and back. I covered the few dark spots and when I closed the door Paul pointed at the smoke plume. It wasn’t the thick black smoke you see in the tourist pictures but a thin grey haze. I’d accidentally outdone myself. I fired her light so the Virginia bituminous instantly caught fire and burned very clean and very hot.

“Nice work.” Paul told me and then he pointed at the pressure gauge. It was climbing back up again. Number 3 was, once again, under full steam.

I was talking to Paul a little while ago and I mentioned that day I spent as an apprentice fireman. He laughed and told me how a good fireman anticipates what the engine needs and is ready to feed it. It depends on the grade of the line, the quality of the fuel and the work you have to get from that engine. I learned how to feed an engine that day and that’s the science. Experience teaches you when to feed the engine and how much. That’s the art.