St Louis-San Francisco 4-8-4 "Northern" Locomotives in the USA

The St. Louis San Francisco Railroad received 25 Northern type locomotives (road numbers 4500 through 4524) from the Baldwin Locomotive Works in 1943. This group was a mix of coal burners that weighed 462,500 lbs and oil burners that weighed 454,000 lbs. The oil burners (road number 4500 through 4502) were assigned to passenger service. All of these 4-8-4s had 74" drivers, 28 x 31 cylinders, a boiler pressure of 250 psi and a tractive effort of 69,800 pounds.

There are four survivors: number 4500 at the Route 66 Station in Tulsa, OK; number 4501 at the Age of Steam Railroad Museum in Frisco, TX; number 4516 at the State Fairgrounds in Sedalia, MO and number 4524 at Grant Beach Park in Springfield, MO.

Class Details by Steve Llanso of Sweat House Media

Class 4500 (Locobase 277)

Data from SL&SF 1947 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for 18 June 2015 reporting the first trio's tender oil capacity, finding the booster's tractive effort, and spotting the 100,000 lb error in the tender weight.) Works numbers were 64437-64451 in August 1942 and 69731-69740 in August 1943.

Based on the CB&Q's O-5 Northern design but with some small differences.. Firebox heating surface included 117.5 sq ft (10.92 sq m) in three thermic syphons and 145 sq ft (13.47 sq m) from the long combustion chamber. Further thermal encouragement came from the Coffin feed water heater. Piston valve diameter measured 14" (356 mm).

The first three engines -- 4500-4502 -- were oil-fired and trailed tenders carrying 6,500 US gallons (24,603 litres) of oil. They ran in passenger service. They were painted blue and white with red letters proclaiming their duty as pulling the Meteor.

The other twelve in the first batch -- 4503 to 4514 -- used coal fuel and pulled freight. Boiler pressure and hence TE varied slightly. These were fitted with Franklin Type E trailing-truck boosters that soon appeared on the earlier engines. All were available for passenger service and were seen on the Meteor and Texas Special. Once the Frisco acquired passenger diesels in 1947, the Frisco placed the 4500s at the head of less-prestigious "General Wood" and "Will Rogers" services.

All 25 engines were "dismissed from service"--as the Frisco described it--in October 1956.

The web site for the restored 4500 gives slightly different measures for heating surfaces.

Principal Dimensions by Steve Llanso of Middle Run Media

Locobase ID277
RailroadSt Louis-San Francisco (Frisco/(SLSF)
Number in Class25
Road Numbers4500-4524
Number Built25
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)19.25 / 5.87
Engine Wheelbase (ft / m)46.50 / 14.17
Ratio of driving wheelbase to overall engine wheelbase 0.41
Overall Wheelbase (engine & tender) (ft / m)92.33 / 28.14
Axle Loading (Maximum Weight per Axle) (lbs / kg)70,620 / 32,033
Weight on Drivers (lbs / kg)280,340 / 127,006
Engine Weight (lbs / kg)474,040 / 209,787
Tender Loaded Weight (lbs / kg)341,300 / 154,811
Total Engine and Tender Weight (lbs / kg)815,340 / 364,598
Tender Water Capacity (gals / ML)18,000 / 68.18
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)24 / 22
Minimum weight of rail (calculated) (lb/yd / kg/m)117 / 58.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)74 / 1880
Boiler Pressure (psi / kPa)255 / 17.60
High Pressure Cylinders (dia x stroke) (in / mm)28" x 31" / 711x787
Tractive Effort (lbs / kg)71,188 / 32290.37
Booster (lbs)9600
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.94
Heating Ability
Tubes (number - dia) (in / mm)206 - 2.25" / 57
Flues (number - dia) (in / mm)63 - 5.5" / 140
Flue/Tube length (ft / m)20 / 6.10
Firebox Area (sq ft / m2)524.50 / 48.73
Grate Area (sq ft / m2)88 / 8.18
Evaporative Heating Surface (sq ft / m2)4766 / 442.77
Superheating Surface (sq ft / m2)1508 / 140.10
Combined Heating Surface (sq ft / m2)6274 / 582.87
Evaporative Heating Surface/Cylinder Volume215.75
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation22,440
Same as above plus superheater percentage27,826
Same as above but substitute firebox area for grate area165,847
Power L129,842
Power MT938.72

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Wes Barris