Nacional de Mexico 4-8-2 "Mountain" Type Locomotives

Class TR-1/TR-2 (Locobase 1375)

Formerly operated by the Florida East Coast. Sold to Nacional de Mexico in 1941, which extended their lifetimes to 1956-1957.

Class TR-3 (Locobase 1376)

Data from NdeM 1946 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Bigger brothers to the ex-FEC TR-1s and TR-2s, these were sold to the Nacional de Mexico in 1945 (14) and 1948 (6). Some operated as late as 1964.

Specifications

Class TR-1/TR-2 TR-3

Locobase ID 1375 1376

Railroad Nacional de Mexico Nacional de Mexico

Whyte 4-8-2 4-8-2

Road Numbers 3200-3209 3300-3319

Gauge Std Std

Builder Alco-Richmond Alco-Schenectady

Year 1923 1924

Valve Gear Walschaert Baker or Walschaert

Locomotive Length and Weight

Driver Wheelbase 18.58' 19.58'

Engine Wheelbase 40.08' 42.17'

Ratio of driving wheelbase to overall engine wheebase 0.46 0.46

Overall Wheelbase (engine & tender) 84.42' 77.52'

Axle Loading (Maximum Weight per Axle)

Weight on Drivers 191500 lbs 217000 lbs

Engine Weight 287000 lbs 321500 lbs

Tender Light Weight 201700 lbs 162250 lbs

Total Engine and Tender Weight 488700 lbs 483750 lbs

Tender Water Capacity 10000 gals 10000 gals

Tender Fuel Capacity (oil/coal) 4000 gals 4000 gals

Minimum weight per yard of rail on which locomotive could run 79.79 lb rail 90.42 lb rail

Geometry Relating to Tractive Effort

Driver Diameter 68" 73"

Boiler Pressure 204.50 psi 204.50 psi

Cylinders (dia x stroke) 25" x 28" 25" x 28"

Tractive Effort 44734 lbs 41670 lbs

Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.28 5.21

Heating Ability

Firebox Area 333 sq. ft 365 sq. ft

Grate Area 63.20 sq. ft 68.77 sq. ft

Evaporative Heating Surface 3303 3812

Superheating Surface 849 944

Combined Heating Surface 4152 4756

Evaporative Heating Surface/Cylinder Volume 207.63 239.63

Computations Relating to Power Output (More Information)

Robert LeMassena's Power Computation 12924.40 14063.47

Same as above plus superheater percentage 15567.18 16854.87

Same as above but substitute firebox area for grate area 82023.27 89458.00

Power L1 18370.35 22104.72

Power MT 845.95 898.30

Specifications
Class	TR-1/TR-2	TR-3
Locobase ID	1375	1376
Railroad	Nacional de Mexico	Nacional de Mexico
Whyte	4-8-2	4-8-2
Road Numbers	3200-3209	3300-3319
Gauge	Std	Std
Builder	Alco-Richmond	Alco-Schenectady
Year	1923	1924
Valve Gear	Walschaert	Baker or Walschaert
	Locomotive Length and Weight
Driver Wheelbase	18.58'	19.58'
Engine Wheelbase	40.08'	42.17'
Ratio of driving wheelbase to overall engine wheebase	0.46	0.46
Overall Wheelbase (engine & tender)	84.42'	77.52'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	191500 lbs	217000 lbs
Engine Weight	287000 lbs	321500 lbs
Tender Light Weight	201700 lbs	162250 lbs
Total Engine and Tender Weight	488700 lbs	483750 lbs
Tender Water Capacity	10000 gals	10000 gals
Tender Fuel Capacity (oil/coal)	4000 gals	4000 gals
Minimum weight per yard of rail on which locomotive could run	79.79 lb rail	90.42 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	68"	73"
Boiler Pressure	204.50 psi	204.50 psi
Cylinders (dia x stroke)	25" x 28"	25" x 28"
Tractive Effort	44734 lbs	41670 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.28	5.21
	Heating Ability
Firebox Area	333 sq. ft	365 sq. ft
Grate Area	63.20 sq. ft	68.77 sq. ft
Evaporative Heating Surface	3303	3812
Superheating Surface	849	944
Combined Heating Surface	4152	4756
Evaporative Heating Surface/Cylinder Volume	207.63	239.63
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	12924.40	14063.47
Same as above plus superheater percentage	15567.18	16854.87
Same as above but substitute firebox area for grate area	82023.27	89458.00
Power L1	18370.35	22104.72
Power MT	845.95	898.30

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.