Steam Locomotives of the Frisco Lines (SLSF)

The Frisco Lines received a total of 65 Mikados with additional booster between 1923 and 1926, based on the USRA Heavy Mikado. The first 35 locomotives had Baker valve gear and were heated with coal or oil, depending on the lines. The locomotives from number 4135 had Walschaert valve gear and termic syphons. Starting with the 4150, the heating surface has been increased. The first 35 locomotives were later also given Walschaert valve gear and thermic syphons, as well as slightly larger driving wheels. They were dismissed from service in 1951 and 1952.

Variant	4100	4100 with thermic syphons	4135	4150

General
Built	1923	1929	1925	1926
Manufacturer	Baldwin	Spingfield	Baldwin
Axle config	2-8-2 (Mikado)
Gauge	4 ft 8 1/2 in (Standard gauge)

Dimensions and Weights
Wheelbase	36 ft 11 in
Rigid wheelbase	16 ft 9 in
Total wheelbase	73 ft 4 in	74 ft 2 in	73 ft 5 in	74 ft 2 in
Service weight	313,000 lbs	344,600 lbs	320,400 lbs	349,660 lbs
Adhesive weight	240,000 lbs	236,200 lbs	244,700 lbs	266,050 lbs
Total weight	550,000 lbs	580,800 lbs	560,900 lbs	582,780 lbs
Axle load	60,000 lbs	59,050 lbs	61,175 lbs	66,513 lbs
Water capacity	12,000 us gal			11,700 us gal
Fuel capacity	4,500 us gal (oil)	34,000 lbs (coal)		4,500 us gal (oil)

Boiler
Grate area	70.3 sq ft
Firebox area	286 sq ft	380 sq ft	381 sq ft
Tube heating area	3,666 sq ft	3,681 sq ft	3,666 sq ft	3,692 sq ft
Evaporative heating area	3,952 sq ft	4,061 sq ft	4,047 sq ft	4,073 sq ft
Superheater area	1,048 sq ft	993 sq ft	1,063 sq ft	1,126 sq ft
Total heating area	5,000 sq ft	5,054 sq ft	5,110 sq ft	5,199 sq ft

Variant	4100	4100 with thermic syphons	4135	4150

Power Plant
Driver diameter	63 in	64 in	63 in
Boiler pressure	190 psi	200 psi	190 psi	200 psi
Expansion type	simple
Cylinders	two, 27 x 32 in

Power
Power source	steam
Estimated power	3,200 hp (2,386 kW)	3,250 hp (2,424 kW)	3,100 hp (2,312 kW)	3,500 hp (2,610 kW)
Optimal speed	34 mph	33 mph		35 mph
Starting effort	59,801 lbf	61,965 lbf	59,801 lbf	62,949 lbf
Booster	11,200 lbf		12,400 lbf	11,200 lbf

Calculated Values
Factor of adhesion	1 : 4.01	1 : 3.81	1 : 4.09	1 : 4.23
Power-to-weight ratio	0.0102 hp/lb	0.0094 hp/lb	0.0097 hp/lb	0.0100 hp/lb
Heating Area Equivalent	7,478 sq ft	7,947 sq ft	8,078 sq ft	8,230 sq ft
Cylinder volume/HAE	1 : 864.34	1 : 813.33	1 : 800.14	1 : 785.36
Adhesive weight/Total	1 : 1.30	1 : 1.46	1 : 1.31
Tractive force/Heating area	1 : 2691.00	1 : 2758.50	1 : 2633.31	1 : 2724.12
Grate area/Heating area	1 : 67.06	1 : 66.49	1 : 67.27	1 : 68.54
Firebox/Tube area	1 : 16.48	1 : 12.30	1 : 12.41	1 : 12.65
Total/Superheater	1 : 3.77	1 : 4.09	1 : 3.81	1 : 3.62

steam locomotive

freight

booster

last changed: 05/2023

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