St Louis-San Francisco 2-8-8-2 "Chesapeake" Locomotives in the USA

Class 2001 (Locobase 6454)

Data from builder's card shown on the FMIG site (12 January 2005). See also "Mallet for the Frisco System", Railway & Locomotive Engineering, Volume XXIII [23], No 12 (December 1910), p. 484; and "Recent Mallet Articulated Locomotives", Railway Age Gazette, Volume 49, No 25 (16 December 1910)., pp. 1144-1145. Works numbers were 48652-48656 and 48734-48735 in October 1910.

The Alco-Frisco tractive effort is given as 83,300 lb (37,784 kg or 379.54 kN). The first five were delivered to the Frisco's sub Kansas City, Fort Scott & Memphis. HP cylinders received their steam through 14" (356 mm) piston valves.

The brief comment notes that these were the most powerful 2-8-8-2s when delivered (and the first from Alco), but that they were unsatisfactory in service. Wes Barris of [] ([], visited 12 January 2005) states that the tender was so small that the locomotives had a very short range. (Locobase also notes that the boiler seems small given the ratios and factors and the tubes too long even with a long combustion chamber.)

On the other hand, the design did offer some interesting features. RAG's report describe the boiler construction as its "most interesting feature". The 6-ft long combustion chamber allowed the builder to place the big firebox behind the rear driving axle. This in turn made room for a throat sheet depth of 18 3/6" (462 mm) and placed the top of grate 26 1/4" (667 mm) below the lowest boiler tube. This latter distance was a good 6-7 (152-178 mm) inches more than usually provided and thus better for grate combustion.

Another was the use of inside steam pipes that dropped down on either side of the combustion chamber section from a T-header that took its steam from the throttle; doubtless the combustion chamber's 9" (229 mm) of water space on all three sides (bottom and two sides) granted such room. The outside pipe sections used copper pipes fitted with an elbow at each end and ball joints at the lower end of the inside pipe and the top of the high-pressure cylinder oneach side. Going to this kind of trouble eliminated the use of a special cast-steel dome to which external steam pipes would have connected.

Despite the design's imperfections, the Frisco superheated these locomotives in the 1920s; see Locobase 8640.

Class 2001 - superheated (Locobase 8640)

Data from StLSF 1930 and SL&SF All Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 8 November 2019 email noting different specs for 2007's tender.)

Despite the weaknesses describe in Locobase 6454, the Frisco's only articulateds received the modifications applied to virtually all locomotives worth the effort. In particular, the engines were superheated and at least three of the engines -- 2001, 2004, 2007 -- later used piston valves on the LP cylinders as well as the HP cylinders using 14" (356 mm) piston valves already installed when the class was delivered in 1910.

In the 1920s, 2001-2005 were assigned to the Kansas City, Fort Smith & Memphis subsidiary while 2006-2007 served the parent Frisco lines. They wound up as switchers of iron-ore trains near Birmingham, Alabama. "Someone could correct me if I'm wrong," comments Wes Barris of [] ([], "but they were probably the largest steam switch engines." At some point, 2007 trailed a tender carrying 9,125 US gallons (31,538 litres) of water and 21 tons (19.1 metric tons) of coal.

The class was "dismissed from service" over a long period. 2005 went in December 1929 at Springfield, Mo. The others all retired in Birmingham, Ala: 2002, 2003, & 2006 all withdrew in July 1935; 2007 followed a few months later in April 1936 and 2001 & 2004 went in April 1939.