The rumours are true; there is a secret tunnel at Barrow Hill.
Unfortunately it's not as exciting as a bolt hole for priests, a pathway to our dungeons for errant employees, or even a wartime route to the old Barrow Hill Station. It is part of the old drainage system.
In the days of steam, one of the dirtiest jobs in the shed was to wash out the locomotives with high pressure water, removing the sludge from the firebox, the tubes and the smokebox. The dirty water drained down into the inspection pits and from there via large diameter tubes into the main ring sewer. This consisted of a tunnel 10 feet below the floor of the roundhouse, located halfway between the turntable and the external walls. This tunnel formed a complete ring around the turntable and it is still beneath our feet today. It is brick built, about three feet high with an arched roof. The water from our vast roof still drains into this system.
From this tunnel the water was piped to the main sewers via oil traps. Of course this tunnel had to deal with lots of solid waste and it was said that one of the jobs of the newest apprentices was to periodically venture down into this tunnel and remove the sediment that quickly blocked it up. Not a job for the faint hearted as one imagines that not only was the job somewhat claustrophobic, dark and damp but there was some interesting wildlife down there. One didn’t want to cross the shed foreman when this job was due!
After years of neglect the tunnel is nearly silted up but it is still possible to see the top of the arched tunnel. Don Cambridge, one of our committee members, has been most of the way around it to check its condition in the early days of the roundhouse restoration, apparently not a nice pastime even with a wet suit and powerful torches.
A simple grate covers the entrance to the tunnel
The pipe entering from the side is the drainage from one of the inspection pits
Sediment is now nearly to the top of the 3ft high tunnel. Someone needs to clean it out soon!
After dark, staff have said you can still hear the sounds of grimy apprentices shoveling the muck from the tunnels into buckets and shouting to their colleagues to "pull t'bucket up"...
Inspection pits are located under every road. They are about 4 feet deep, not deep as you might expect as the height of the locomotive had to be taken into account. With driving wheels of 6 feet diameter, engineers standing in the pit were working with their heads just below the axles. Lighting was provided originally by flare lamps but eventually electric lighting was installed.
A photograph taken the last time Don went in to try and desilt, it actually the part that leaves the circular bit and heads outside to the river. It is clean because it is the section that gets flushed by rainwater the most.
For those who read the London news, no Fatbergs down here, just oily sludge!