Illinois Central 4-8-2 "Mountain" Type Locomotives

Introduction

The Illinois Central Railroad purchased its first "Mountain" type locomotives from the American Locomotive Company in 1923. This first order consisted of fifteen (road numbers 2400 through 2414) locomotives which had 28 x 28 cylinders, 73.5" drivers and a 230 psi boiler pressure. They exerted 58,138 lbs of tractive effort and weighed 362,500 pounds.

In 1925, the IC took delivery of twenty-five (road numbers 2415 through 2439) more,this time, from the Lima Locomotive Works and in 1926 another twenty (road numbers 2440 through 2459) came from ALCO. These forty-five locomotives were very similar to the fifteen received in 1923, except for an increase of 5,000 lbs in locomotive weight.

The Paducah, KY Shops of the Illinois Central built a total of 76 "Mountain" type locomotives between 1937 and 1943. The 2500 series were built at the IC Paducah shops from older IC 2-10-2 boilers originally built by Lima.

Number 2613 was used on the L&N Centennial between Louisville and Nashville on Oct 24, 1959. It also ran two excursions out of Louisville to Paducah on May 14, 1960 and to Dawson Springs on Oct 2, 1960. It was kept in the Paducah roundhouse and was in freight service in the Paducah area a few times. It was almost preserved when it was offered (for sale) to the Kentucky Railway Museum. However, the IRM declined the offer and the engine was scrapped. There are two surviving IC "Mountains", number 2500, at a park in Centralia, IL and number 2542 at the IC depot in McComb, MS.

Roster by Richard Duley

QtyRoad NumbersYear BuiltBuilder
152400-24141923ALCO
252415-24391925Lima
202440-24591926ALCO
562500-25551937-1943IC
202600-26191942-1943IC

Class Details by Steve Llanso

Class 2400 (Locobase 1356)

Data from IC 9 -1928 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. (Thanks to Chris Hohl for his 11 November 2012 email correcting builder attribution and road number series.) Works numbers were 64569-64583 in 1923.

This was the IC's first batch of Mountains and the firebox heating surface included 48.3 sq ft (4.5. sq m) of arch tubes. The subsequent batches -- see Locobase 6702 -- introduced thermic syphons into the firebox.

Class 2415 (Locobase 6702)

Data from IC 9 -1928 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. (Thanks to Chris Hohl for his 11 November 2012 email correcting builder attribution and road number series.) Lima works numbers were 6884-6909 in 1925 and Schenectady works numbers were 67039-67058 in 1926

The first 15 locomotives in the IC's 4-8-2 fleet are described in Locobase 1356. The current record shows the later batches of Mountain. The biggest difference came in the firebox heating surface where the arch tubes were replaced by 115.5 sq ft of thermic syphons.

Class 2500 (Locobase 6703)

Data from IC 1955 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The specs refer to the version that had two arch tubes and four thermic syphons. Together the two types of appurtenances contributed 132 sq ft (12.25 sq m) to the firebox heating surface.

The IC took a different path in its development of motive power by rebuilding many of its locomotives. This class is a good case in point. The boilers came from the Lima-built 2900 class of 2-10-2s. Beginning in the mid-1930s, IC Paducah shops took the 2900 boilers, reinforced them, and laid them on a new frame. This engine bed comprised a single casting that included the cylinders and the air-pump reservoir.

One by one, beginning in March 1937, 55 of this class were delivered over the next five years. After the rebuilds came the 20 locomotives of the 2600 class (see Locobase 3156), which continued the same design, but were newly built.

Class 2600 (Locobase 3156)

Data from IC 1955 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. The specs show the variant that had Type HA superheaters (which had larger-diameter superheater elements); other engines had the Type A that contained 1,242 sq ft of heating surface.

These behemoths were among the largest Mountains ever built. They kept the square diameter x stroke dimensions of the earlier 2400s, but increased the size. The firebox heating surface included 83 sq ft (7.7 sq m) of arch tubes (which Locobase considers counter-trending.). The specs show the variant that had Type HA superheaters; other engines had the Type A that contained 1,242 sq ft (115.4 sq m) of heating surface.

Like the fifty-five 2500s of the late 1930s, these engines had cast-steel engine beds that included the cylinders and air reservoirs. Unlike the 2500-class engines, which used reinforced boilers from the 2900-class Santa Fes, 2600-2619 were new from the rail up.

Offering a prodigious power output on 70" drivers, the Mountains gave good service in freight service of all kinds, according to John S. Ingles (in Drury, 1993), "...even coal trains moved faster behind 4-8-2s than they had behind 2-10-2s."


Specifications by Steve Llanso
Class2400241525002600
Locobase ID1356 6702 6703 3156
RailroadIllinois Central (IC)Illinois Central (IC)Illinois Central (IC)Illinois Central (IC)
CountryUSAUSAUSAUSA
Whyte4-8-24-8-24-8-24-8-2
Road Numbers2400-24142415-24592500-25542600-2619
GaugeStdStdStdStd
BuilderAlco-SchenectadyseveralICIC
Year1923192519371942
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase19.50'19.50'18.25'18.25'
Engine Wheelbase42.25'42.25'42.25'42.25'
Ratio of driving wheelbase to overall engine wheebase 0.46 0.46 0.43 0.43
Overall Wheelbase (engine & tender)77.79'77.79'83.33'92.34'
Axle Loading (Maximum Weight per Axle)60800 lbs62300 lbs
Weight on Drivers243500 lbs247000 lbs280500 lbs293880 lbs
Engine Weight362500 lbs367500 lbs409500 lbs423893 lbs
Tender Light Weight191500 lbs205300 lbs219500 lbs370500 lbs
Total Engine and Tender Weight554000 lbs572800 lbs629000 lbs794393 lbs
Tender Water Capacity10000 gals10000 gals11000 gals22000 gals
Tender Fuel Capacity (oil/coal)18 tons18 tons24 tons26 tons
Minimum weight of rail (calculated) on which locomotive could run101 lb/yard103 lb/yard117 lb/yard122 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter73.50"73"70"70"
Boiler Pressure225 psi225 psi240 psi275 psi
Cylinders (dia x stroke)28" x 28"28" x 28"30" x 30"28" x 30"
Tractive Effort57120 lbs57511 lbs78686 lbs78540 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.26 4.29 3.56 3.74
Heating Ability
Firebox Area384.70 sq. ft451 sq. ft518 sq. ft467 sq. ft
Grate Area75.40 sq. ft75.40 sq. ft88.30 sq. ft88.30 sq. ft
Evaporative Heating Surface4643 sq. ft4710 sq. ft5246 sq. ft5195 sq. ft
Superheating Surface1227 sq. ft1227 sq. ft1285 sq. ft1619 sq. ft
Combined Heating Surface5870 sq. ft5937 sq. ft6531 sq. ft6814 sq. ft
Evaporative Heating Surface/Cylinder Volume232.67236.03213.74242.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16965169652119224283
Same as above plus superheater percentage20528205282543030110
Same as above but substitute firebox area for grate area104735122785149184159247
Power L124323247042213333165
Power MT880.87881.99695.83995.18

Photos

Reference

Credits

Introduction and roster provided by Richard Duley. Class details and specifications provided by Steve Llanso of Sweat House Media.