Class 2900 (Locobase 237)

Data from 1947 Locomotive Cyclopedia tables.

Thermic syphons (30.5 sq ft) in the 84-in combustion chamber only. Firebox heating surface includes 124 sq ft in the combustion chamber as well. Steam admission through 15" piston valves.

These 30 engines were built to the #3765 design (Locobase 236), but because of wartime restrictions some of the parts were heavier to offset the lack of high-tensile alloys. As a result of the substitutions, these locomotives became the heaviest passenger locomotives ever built.

AT&SF drawings show slightly different EHS (5319 sq ft), weight on drivers (295,000 lb) and total engine weight (510,000 lb).

Retired in 1959.

Class 3751 (Locobase 233)

Data from 1930 Locomotive Cyclopedia tables.

Firebox had combustion chamber, boiler fitted with Elesco feedwater heater. According to the San Bernadino Railway Historical Society's web site (www.sbrhs.org/history.html consulted in April 2002), the Santa Fe's first Northern combined the conservative boiler pressure of 210 psi with many state-of-the-art features. Among the latter were the cylinders cast integrally with the bed, Nicholson thermic syphons in the firebox, Duplex stoker. Up front was the front-end American throttle, Type E superheater. Valve travel amounted to 9" through a multiplying lever in the Walschaerts valve gear, which was operated by the Ragonnet power reverse gear. Also note the superpower tube & flue distribution.

A measure of this design's impact, according to Drury (1993), lies in its being able to pull 33% more tonnage while burning 19% less coal. (Put another way, for every pound of coal, the 3751 evaporated 6.74 pounds of water -- 43% more than the Mountain.)

Ran between Kansas City and Los Angeles pulling up to 26 cars on the level and 15 up a 2% grade. As a freight hog, the 3751s rolled 105 loaded cars of 5,949 tons at 45 mph on level track. Maximum drawbar horsepower measured at 40 mph was 3,220 hp. Top speed rating from introduction was 70 mph. And the distances covered! From Los Angeles eastbound, the engine might travel to La Junta, Col (1,235 mi), Wellington, Kan (1,535 mi), or Kansas City, Kan (1,789 mi).

Still, according to Lloyd E. Stagner's excellent summary of the Santa Fe 4-8-4s in Trains Magazine (found on the web at http://www.wheelsmuseum.org/stagner.html), the 30" cylinders produced high back pressures that "proved troublesome, resulting in a loss of power at higher speeds ...a retired Santa Fe master mechanic who knew the 3751 class well ... remarked that as built, 'they smelled of lemon', due to the inability of the 15" piston valves to get rid of the exhausted steam efficiently."

14 built in 1927, converted to oil burners in 1937-38. A more significant rebuild saw 10 engines get new frames, lengthened smokebox, new rods, 80-in Boxpok drivers and Timken roller bearings on all axles in 1939-1940. After the rebuild, which also included redesigned steam passages and steam pressure raised to 230 psi, the engines were rated at 90 mph and often ran at 100 mph or more.

The class retired in 1956-1957.

Class 3755 (Locobase 443)

Firebox had combustion chamber and thermic syphons, boiler fitted with feedwater heater.

Members of 3751 class, but given a separate listing in 1930 Locomotive Cyclopedia, from which this data is taken.

According to Lloyd E. Stagner's excellent summary of the Santa Fe 4-8-4s in Trains Magazine (found on the web at http://www.wheelsmuseum.org/stagner.html), 3755 & 56 had Dupont stokers and butterfly doors, while 3757-3760 had Duplex stokers and vertical doors.

Class 3760 (Locobase 235)

Firebox had combustion chamber and thermic syphons, boiler fitted with feedwater heater. Members of 3751 class, but given a separate listing in 1930 Locomotive Cyclopedia, from which this data is taken.

Lloyd E. Stagner's excellent summary of the Santa Fe 4-8-4s in Trains Magazine (found on the web at http://www.wheelsmuseum.org/stagner.html) says that 3764 was delayed in order to fit Caprotti poppet valve gear. Tests were inconclusive, but in any case, the assembly "simply was too light for the heavy service required on big locomotives ...and it had the further disadvantage of requiring specialized maintenances."

Class 3765 (Locobase 236)

Data from 1947 Locomotive Cyclopedia tables.

Thermic syphons in the 84-in combustion chamber only. With Engine #3765, ordered in 1938, the Santa Fe Northern design underwent several changes. The design featured revised cylinder dimensions, substantially higher boiler pressure, and a modified cut-off (limited to 60% of stroke) to supply the same tractive effort with larger drivers.

As Lloyd E. Stagner points out in his history of the Santa Fe 4-8-4s in Trains Magazine (found on the web at http://www.wheelsmuseum.org/stagner.html), the change in cylinders was intended to eliminate the back-pressure problem posed by the 30" pistons in use up to that point. The firebox now had 3 thermic syphons, Timken roller bearings on all engine axles, and all manner of up-to-date equipment.

Also beginning at #3765, fuel was changed from soft coal to oil. Engines 3776-3785 were ordered in 1941; see Locobase 234. Together with the Union Pacific FEF series and the New York Central's Niagaras, these engines were the highest expression of ultra-long-distance passenger power in US service.

Nickel-steel boilers replaced in 1949-1952, engines retired in 1959.

Class 3776 (Locobase 234)

Data from 1947 Locomotive Cyclopedia tables.

Based on the 3765s (Locobase 236), but with further enhancements. Firebox heating surface included 29 sq ft of thermic syphons in the combustion chamber only. 10 delivered in 1941, nickel-steel boilers replaced in 1949-1952, class retired in 1956-1959.

See Lloyd E. Stagner's excellent summary of the Santa Fe 4-8-4s in Trains Magazine (found on the web at http://www.wheelsmuseum.org/stagner.html)