Class 1501 (Locobase 14231)

Data from Baldwin, DeGolyer, Volume 50, pp. 212-228. See also "Mikado 2-8-2 Type Locomotive for the Illinois Central", Railway and Locomotive Engineering, Volume 27, No 7 (July 1914), p. 243. (Thanks to Wes Barris for his 9 July 2021 email catching confusing typos in the works number list.) Works numbers were 41373-41378, 41399-41412, 41423-41452 in May 1914.

Following on from the large order filled by Baldwin in 1911-1912 (Locobase 1354), this batch was only slightly different. Firebox heating surface area included 32.2 sq ft (2.99 sq m) from four arch tubes. Fifteen inch (381 mm) piston valves supplied steam to the cylinders. The IC claimed that in replacing saturated-boiler 2-8-0s on freight trains, they were hauling 30% more tonnage per train with "no increase in actual coal consumption per trip." Four two-inch tubes penetrated each water leg in the firebox to bring more air to the grate.

The basic design would be repeated for twelve years and ultimately comprise 517 locomotives all told.

Some of the class later exchanged two of the arch tubes for 64 sq ft (5.95 sq m) of thermic syphons, which increased direct heating surface area to 307.2 sq ft (28..54 sq m). With the tube count decreasing by six, the evaporative heating surface area increased to 4,093 sq ft (380.25 sq m). Others gave up all the arch tube area in favor of 60 sq m (5.57 sq m) in circulators. Firebox heating surface area increased to 290 sq ft (26.94 sq m) and EHS increased to 4,128 sq ft (383.50 sq m).

A few decades later in the late 1930s and early 1940s, many of this class were converted to heavy 0-8-2 switchers by removing the leading truck.

A few more mated the chassis of one 2-8-2 with the boiler of another and had the rear truck deleted in favor of a fifth driven axle, thus becoming 2-10-0s.

Class 1551 (Locobase 1354)

Data from IC 1913a Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 42, pp. 137+. Works numbers were

1911

May 36577-36581; July 36641-36660, 36714-36716; August 36745-36746, 36757-36761, 36810-36814; October 37030-37039; November 37176-37180, 37254-37258; December 37402-37405.

1912

January 37443-37467, 37482-37490; February 37502-37503, 37507-37508; October 38563-38573; November 38664, 38724-38859.

Design by Edward C. Harriman. These were built by Baldwin and Lima. Baldwin delivered the first 150 in 1911-1912. As delivered, their fireboxes were initially bare of supplemental devices, but even before delivery, the spec had been changed to add 32 sq ft (2.97 sq m).

Also the initial superheater area calculation of 1,093 sq ft revised in ink to 886 sq ft (82.31 sq m), which changed the superheater percentage to 18%. This change brought the balance much closer to the average of several dozen other Schmidt Type A installations. Even though all later Illinois Central diagrams show the original figure. Locobase chose the lower number as being much more in keeping with practice and in recognition of the change in the figure shown in ink in the 1912 specs.

All of the Mikes in this long run (517 locomotives all told) had 15" (381 mm) piston valves. Some in this large stud of 2-8-2s were later fitted with 60 sq ft (5.6 sq m) of circulators, which increased firebox heating surface to 293.2 sq ft (27.2 sq m).

The Baldwin specs contain an interesting way to view the dimensions of a typical US locomotive of the time. Supplemental paragraph 47 says that the 36 5 3/8" tubes in each engine measured a total lineal distance of 782 ft 2 in (Locobase converts that to 238.4 metres or 0.129 nautical miles). Add to that 262 2" tubes that, laid end to end, extended more than a statute mile (5,742 ft 9 in or 1.75 km).

So large a class went through many variations. One significant sub-group was a large set of 0-8-2 heavy switchers (created by removing the leading truck). Others made up part of the 3600 class of 2-10-0s, often made up of the chassis of one 2-8-2 and the boiler of another.

Class 1600 (Locobase 7044)

Data from IC 1913a Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 42, pp.152+. Works number was 38859 in November 1912.

All of the Mikes in this long run of 2-8-2s delivered to the IC had 15" (381 mm) piston valves. This one apparently differed initially in the use of a Gaines patent combustion chamber (see the specification's supplemental instruction 41). The spec refers to an earlier Central of Georgia Mikado order for details. For a full description of the Gaines combustion chamber's intended effect on combustion, see Locobase 4228.

Later modifications would lead to a very different boiler.

Class 1600 - with syphons (Locobase 11187)

Data from IC 4 - 1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

The IC had a lot of Mikados to work with when it began investigating such boiler updates as thermic syphons in the firebox and increased superheater area. For its guinea pig, it seems to have chosen the odd-ball 1600 (Locobase , which was completed in 1912 with a Gaines combustion chamber that shortened tubes by almost three feet. In the 1920s, the shops fitted this locomotive with a new boiler that had 64 sq ft of syphons adding to the firebox heating surface.

Class 1701 (Locobase 7045)

Data from IC 4 - 1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 56, pp. 149+. See "Thermic Syphons Tested at the University of Illinois", Railway Age, Volume 90, No 2 (10 January 1931), pp. 141-146.

also Lima works numbers were 5005-5014 delivered in 1915, 5162-5208 in 1916.

Baldwin added 48739 in May 1918; 48892, 48952, 49000 in June; 49156-49157, 49236, 49303, 49353, 49403-49404, 49476, 49552, 49641 in August; 49921-49922 in September; 50550, 50736 in November; 50876 in December; 51086, 51120-51121, 51165-51167, 51191 in January 1919; 51258, 51342-51343, 51387-51388 in February; 51517-51518, 51564, 51590 in March. Lima added to the stud with fifty more, works numbers 5696-5745, in 1919

As noted in Locobase 1354, the run of Mikado production for the IC was long and relatively unvaried (517 locomotives all told). But different builders managed to alter the specs just slightly. All of the Mikes had 15" (381 mm) piston valves.

Note: The Baldwin specifications credit the superheater with 887 sq ft (82.4 sq m) of area, while the IC diagrams consistently show 1,093-1,099 sq ft (102.4 sq m). Reviewing the more than three dozen 2-8-2 entries that show superheater flue counts of 36, outside flue diameters of 5 3/8" and 20-21 feet of tube lengths indicates that most stated areas in the upper 800s, but that the IC's values clustered around the higher number.

The most likely reason was a difference in the way that the IC calculated superheater area (measuring the outside diameter of the element, e.g.). Locobase does not believe the diagrams were showing "equivalent heating surface area." That figure, which multiplied each square foot of superheater area by 1.5 to try to express its greater effect on power, would be 1,331 sq ft (123.65 sq m).

It's possible that the elements in the IC engine were a bit bigger than those in earlier Mikados of the same configuration.

Locobase 16322 shows the syphons upgrade applied to many of this class and Locobase 16323 describes a more extensive update including a combustion chamber and security circulators.

Class 1701 - with thermic syphons (Locobase 16322)

Data from IC 12 - 1937 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Thermic Syphons Tested at the University of Illinois", Railway Age, Volume 90, No 2 (10 January 1931), pp. 141-146.

As noted in Locobase 1354, the run of Mikado production for the IC was long and relatively unvaried (517 locomotives all told). But different builders managed to alter the specs just slightly. All of the Mikes had 15" (381 mm) piston valves.

The RA report in January 1931 detailed tests conducted on 1700-class engine #1742 that showed a relatively small installation of two thermic syphons and a brick arch increased general boiler efficiency 8.47 percent. Equivalent evaporation per pound of dry coal rose by 7.74 percent . The details of the report include observations that a relatively inefficient firebox may have led to an understatement of the real benefit.

Whatever conclusions others may have drawn about thermic syphons, the IC fitted similar installations in a large number of the 1700 class. A reconfigured firebox included a reduced layout of fire arch tubes that added a mere 16.0 sq ft to the firebox heating surface area. The syphons contributed an additional 73 sq ft (6.78 sq m) of what the tests suggested was considerably more effective.

By 1937, more than 50 locomotives had been so updated.

Class 1800 (Locobase 9471)

The data comes from the IC 1955 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 20 April 2015 email noting the loaded weight for the engine--Locobase had mistakenly identified the figure as the engine's light weight.)

The Locobase reader should not take the count of engines as gospel - few lists are more confusing than the IC's rebuilds. Take, for example, this group of 21 engines neatly grouped under one set of road numbers. There are Baldwins (12), Limas (8) and an Alco-Schenectady (1) ranging in birth date from 1914 to 1923.

Also observe that on the single diagram, three different boilers are shown. All have 60 sq ft (5.55 sq m) of security circulators in addition to the combustion chamber; one version (shown in the specs) has 203 tubes, the other 199. The third variant didn't have a combustion chamber, which meant it retained the 20-ft, 6-in (6.25 m) tube length, as well as 256 fire tubes.

Class 1800 - boiler firebox update (Locobase 16323)

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

At some later date after the IC's Paducah Shops fitted some of its large Mikado stud with thermic syphons (Locobase 16322), the railroad looked at a very different remake of the boiler and firebox. In contrast to the minor reduction in small tubes in the earlier update, the new boiler featured the insertion of a combustion chamber that added 48 sq ft (4.46 sq m to heating surface and 60 sq ft (5.57 sq m) of Security circulators.

Shorter tubes and flues cut the evaporative heating surface area, which supplied more cylinder volume than the original engines and the 14" (356 mm) piston valves were one inch smaller. But the new layout increased the proportions of both the firebox and superheaters to combined heating surface areas. Moreover, the new boiler's pop-off point was set 30 psi (2.07 sq m) higher.

Class 1883 (Locobase 7046)

Data from IC 4 - 1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers ran from 63611 to 63635.

Although following the general lines of the big Mikado program that supplied over 500 2-8-2s to the IC between 1911 and 1923 (517 locomotives all told), this small batch of Schenectady engines is shown with more than 200 sq ft (18.58 sq m) less superheater area. Locobase doesn't know why there would be such a difference. The last batches procured later the same year (Locobase 20) reverted to the larger superheat area. This may be an instance of a combustion chamber taking up space in the boiler, but the evaporative heating surface was unchanged. So was the firebox heating surface, which included 31.6 sq ft (2.94 sq m) of arch tubes. All of the Mikes in this long run had 15" (381 mm) piston valves.

Class 1908 (Locobase 20)

Data from the IC 4 -1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 67, pp. 386+ for the Baldwins. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .)

The last 110 of a series of 517 locomotives that began in 1911 as a design by Edward C. Harriman. hese were built by Baldwin, Alco-Schenectady, and Lima. Firebox heating surface included 15.8 sq ft (1.45 sq m) of arch tubes, 64 sq ft (5.95 sq m) of Nicholson thermic syphons. All of the Mikes in this long run had 15" (381 mm) piston valves.

Many of the earlier Mikados were rebuilt using similar boiler pressures and firebox changes. See Wes Barris's entry on IC Mikados at [] (accessed 20 March 2006).

Class I (Locobase 6082)

Data from the 1926 Alabama & Vicksburg locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange and IC 3 - 1933 Locomotive Diagrams from the same source.. See also DeGolyer, Volume 51, pp. 254+. Works numbers were 42739-42742 in December 1915, 51675 in April 1919; 53059-53060 in February 1920; and 53091, 53119 in April.

Small Mikados for both the Alabama & Vicksburg, Shreveport & Pacific. The firebox had a patented Gaines combustion chamber. For a full description of the Gaines combustion chamber's intended effect on combustion, see Locobase 4228.

The 350-354 were renumbered 360-364 in 1920 when they were joined by the 357 and 365-368. For some reason, 357 was not renumbered.

Class I (Locobase 15199)

Data from the 1926 Alabama & Vicksburg locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange and IC 3 - 1933 Locomotive Diagrams from the same source. See also DeGolyer, Volume 68, pp. 100+ and "2750: Young Valve Gear", Brotherhood of Locomotive Firemen and Enginemen's Magazine, Volume 63, No 7 (1 July 1917), pp. 26.Works numbers were 58017-58018 in September 1924.

The first of these small Mikados were produced for Vicksburg, Shreveport & Pacific, New Orleans & North Eastern, and the Alabama & Vicksburg (see Locobases 6082 6095, and 16350). The current two repeated the power dimensions found in the earlier I-class, but used Young valve gear to actuate similar-sized 13" (331 mm) piston valves. The boiler was restructured for more superheat with the addition of two more superheater flues and 21 fewer tubes. They also had two Nicholson thermic syphons that added 52 sq ft (4.8 sq m) to the direct heating surface.

The firebox had a patented Gaines combustion chamber. For a full description of the Gaines combustion chamber's intended effect on combustion, see Locobase 4228.

Answering a query from a brother in the union, the BLFE supplied a detailed description of the Young gear, The biggest difference in the mechanism from the Walschaert gear was the absence of an eccentric on the driver. Instead, the Young used a rock shaft to communicate the movement of a crank arm on one side to the crank arm on the other side.

In response to a question about its configuration and advantages, the BLFE replied in part:

"The principal advantages claimed for the Young valve, valve gear and reverse gear, a combination that usually goes together (although the valve gear can be used with any type of valve, or the reverse gear can be used with any type of valve gear), are an improved distribution of steam, and saving all loss from leakage; more effective valve lubrication, resulting in a reduction in friction, and a more accurate valve adjustment for prolonged periods.

It's clear from other commentaries that a big advantage lay in the increased valve travel: "With this type of gear a longer valve travel can be obtained than with either the Walschaert or the Baker, and, on account of the increased valve travel, a greater port opening is possible, thereby allowing for the reduction in the diameter of the valve. In other words, it is claimed that in early cut-offs a Young valve gear, with 11-inch [279 mm] valves, will supply as great a volume of steam to the cylinders as 16-inch [406 mm] valves are capable of with the Walschaert gear."

Impressive. See Locobase 6591 for a report by "4-12-2" on Union Pacific trials that appeared to substantiate the claims.

The BLFE respondent concluded his assessment as follows:

"The gear has many good features to commend it, in that it is possible to obtain longer valve travel, as stated before; that all movement is in direct lines, with the wearing parts consisting of pins and bushings; that the valve can be made much lighter, and, owing to the difference in construction, that is, having the packing rings fit into the valve chamber, instead of into the valve itself, the valve rings can always be maintained a much better fit in this way, keeping them always steam tight, doing away with the possibilities of steam leakage, something very hard to control in this day of superheated steam."

Both were taken into the Illinois Central in 1926 and renumbered 3971-3972. By the time the 1933 diagram book appeared, all of the class had been refitted with Walschaert gear. In 1940, the IC modified both engines to operate as 0-8-0 switchers made more powerful by raising the boiler pressure to 220 psi and reducing driver diameter to 55" (1,397 mm); their new road numbers were 3498-3499.

Both were sold for scrap in 1954 (3498 in January, 3499 in April).

Class I (Locobase 16350)

Data from DeGolyer, Volume 59, pp. 68+ and Volume 68, pp. 93+. See also IC 3 - 1933 Locomotive Diagrasm supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collection. See also "New Locomotives for Alabama & Vicksburg", Railway Journal, Volume 29, No 2 (February 1923), pp. 14-15. Works numbers were 51644 in March 1919 and 55481 in June 1922.

Duplicating the design used in two New Orleans & Northeastern 2-8-2s (Locobase 6095) and nine Vicksburg, Shreveport & Pacific engines (Locobase 6082), fellow Queen & Crescent Route railroad A&V bought its first Mikado in 1919. Like the earlier engines, the 460 had annealed Vanadium cast steel frames, 13" (330 mm) piston valves, and 29 sq ft (2.69 sq m) of arch tubes. Given the limits imposed by rail weights of 75 lb/yard (37.5 kg/metre), the design provided freight power in a small package.

461 introduced Young valve gear to this design when it was delivered in 1922. Unlike the later pair of A&Vs, which also had Young valve gear (see Locobase 15199 for a full discussion of the gear design), the 461 used the same boiler design as the earlier I class engines.

All three Young-gear locomotives had switched to Walschaert gear by the time the IC's 1933 diagrams were prepared.

In 1937, the IC rebuilt both engines as more powerful 0-8-0s of greater power by using smaller 55" (1,397 mm) drivers and boosting boiler pressure to 220 psi (15.17 bar). Renumbered 3493, the switcher remained in service into the late 1940s.