Toronto, Hamilton, & Buffalo 2-8-4 Locomotives in Canada

Class As (Locobase 62)

Data from "Class 284 S 383-Built for the Toronto, Hamilton & Buffalo" builder's photo and data card for Order No. Q-351 July 1928. See also "Berkshires In Ontario Classic Steam #25" post by "Rob" aka trolleyboy dated Sat, Mar 15 2008 11:19 PM at [] . See also William Blevins, "The Top Twenty", Canadian Rail, No 306 (July 1977), pp. 197-213. (My thanks to Chris Hohl, whose inquiry about the valve gear led to much research and a substantial expansion of the entry and for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error Hohl's 24 July 2023 email pointed out the original boiler pressure and the use of a booster and supplied the MLW builder's card as well.) Works numbers were 67573-67574 in June 1928.

Boiler had Coffin feedwater heater, valve motion limited cutoff, duplex stoker. Note how much lighter for its tractive effort this engine was than many others. Chris Hohl's email noted that the original boiler pressure setting as described in Montreal's builder's card read 210 psi (I14.48 bar). At that pressure, the A's factror of adhesion meaured a reasonable 3.97 (adhesion weight divided by tractive effort). Raising the boiler pressure 30 psi lowered it to the possibly quite slippery 3.28 shown in the specs.

Rob's post offered a lot of useful background to this class. He notes that TH&B traffic up the Niagara Falls Escarpment entailed scaling a 1.04% grade for 4.41 miles (7.1 km). Existing Gs Consolidations (Locobase 14707) couldn't manage the loads. Tests with a New York Central Mikado and a Boston & Albany Berkshire led the railroad to opt for the latter. But there was a hitch, according to Rob: "For reasons of economy it was decided to build the locomotives in Canada, Lima had no Canadian subsidiary so tooling would have been prohibitively expensive for such a small order. As luck would have it Alco had just finished an order for 12 Berks of their design for the C&NW so the patterns were promptly rushed to MLW Alco's Canadian wing."

Blevins observed (p. 203) that the As were the "closest approximation to the 'Super-Power' of the Lima Locomotive Works (USA) to be found in Canada.'

The two A class engines arrived on the property on July 8 and July 12 and took on their regular assignment "...the starlight freight run between Hamilton and Michigan Centrals Victoria Yard in Fort Erie Ontario, a 50 mile (80.5 km) run. " Rob added that the pair was capable of 65 miles per hour (104.7 km/h) in service, suiting them to stand in for 4-6-2s and 2-8-2s on the Escarpment.

Not long after the TH&B put the pair in service, however, they found their tractive power limited them to a 2,450 ton train load limitation without a helper engine. To address that issue as well as problems with slippage and stalling when starting from rest, the shops installed Franklin Railway Supply traling-truck boosters in August 1929. According toan FRS advertisement facing page 665 in the 14 April 1932 Railway Age, A class starting trainloads increased to 3,100 tons.

William Blevins's calculation on page 200 established that the boiler could sustain an evaporative rate of 68,690 lb (31,157 kg)/hour. Its calculated max drawbar horsepower of 3,320 (2,477 kW) was topped only by the Canadian Pacific's two 4-8-4s. Measured at 65% cutoff, the tractive effort was still a healthy 69,000 lb (31,298 kg).

After a 25-year career, the two As were the last freight steam to operate on the TH&B. Both engines went to the scrapper in November 1953.