Canadian Pacific Railway #8000, class T4a, was an experimental 2-10-4 locomotive that enjoyed a unique multi-pressure boiler. The locomotive was built in May 1931 at CPR’s Angus shops.
The unique boiler, much longer than those on other CPR 2-10-4’s, was designed jointly by the staffs of the CPR, the American Locomotive Company (ALCO), and the Elesco Feedwater Heater Co. It employed three chambers utilizing steam at three different pressures—250 pounds, 800 pounds and 1600 pounds. The 1600 pound steam was not used for traction, but was used in an internal heat transfer circuit. The locomotive was a three cylinder beast with
the two outboard cylinders using the 250 psi steam, and a centre third cylinder using steam at 800 psi . All this made #8000 a very complex locomotive.
She was also a giant—the locomotive weighed in at 485,000 pounds plus the tender at 300,000 pounds, for a total of 392.5 tons. She measured 99 feet 3 inches, and boasted a 90,000 pound tractive force (17,000 pounds more than a 5900)—enough to pull up to 150 40-ton freight cars.
The Vancouver Province of May 10, 1931 reported, “Roaring westward from Montreal to take up work in freight and passenger service in the Rockies, the new type locomotive 8000 will not cause interest in just the mechanical and railroad circles alone, it will have additional interest in the fact that 400 men will be employed all summer long in laying 130 lb. steel rails for the monster engine between Revelstoke and Field. The 8000 supercedes the 5900, which was formerly the largest locomotive”.
Outshopped in May 1931, the 8000 was kept around Montreal until September 1931 for testing. It was then sent to Revelstoke to be used in heavy freight service between Revelstoke and Field. Being a complex locomotive, problems emerged in the operating environment. Changes were made to the firebox using a special steel imported form England, the work being done at the Calgary Ogden shops. The locomotive continued in service until September 23, 1936 accumulating over 50,000 miles of heavy duty.
At this point it was sent to Montreal’s Angus shops for an overhaul. The overhaul never happened, and #8000 languished at Angus until December 1940 when she was scrapped. Parts were salvaged for use in other CPR locomotives.
More information and photos of #8000 can be found in Omar LaValee’s book Canadian Pacific Steam Locomotives. Max Jacquiard crested a painting titled “8000 On Stoney Creek Bridge” that captured this marvelous monster in the service she was designed for. #8000 lives on in images and memories, a grand but relatively short lived experiment in railway technology.
