Class 101/K/Ms (Locobase 16039)

Data from Excel spreadsheet supplied by Chris Hohl in his 31 March 2015 email and DeGolyer, Volume 38, pp. 288+ and Volume 48, pp. 183+. (Hohl's 2015 email also corrected the range for the class's road numbers.) Baldwin's works numbers were 37244-37248, 37259, 37384 in November 1911, 40662-40663 in September 1913, 40722 in October.

This batch of ten Mikados was delivered to the V&SW at the same time identical engines were produced for the Mobile & Ohio (Locobase 13796). They followed the Southern's K-class Mikado design. The last three, delivered almost two years after the first seven, put 3,400 more pounds (1,542 kg) on the drivers. All of the Ks were delivered with fireboxes able to accept arch tubes, but not fitted with them. They all had 14" (356 mm) piston valves.

At the end of 1916, the V&SW was incorporated into the Southern and the 101s were renumbered. By the end of the 'teens, all would be equipped with 32 sq ft (2.95 sq m) of arch tubes and have their boiler pressures set to 180 psi (12.4 bar).

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Class 301/K/Ms (Locobase 16041)

Data from DeGolyer, Volume 48, p. 191+. Baldwin's works numbers were 40746-40749 in October 1913 and 40822 in November. Alco's Richmond works number was 54788 in 1914.

Baldwin was building large batches of K-class Mikados (Locobase 44), its subsidiary roads were buying smaller amounts. Part of the Southern's Queen & Crescent Route, the railroad's infamous "Rathole Division" in Kentucky and Tennessee demanded as much tractive power as its limited tunnel clearances would permit. These engines were delivered without arch tubes, although the specs state that the firebox's arch could accept them later.

Boiler pressure would soon be set to 200 psi

All of the 900s were renumbered by the Southern in 1917.

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Class 306/K/Ms (Locobase 11077)

Data from SRY 5 - 1943 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 5389-5394 in July 1917.

Although placed in class K, this batch of Mikes had larger boilers and fireboxes than the widely used Ks bought earlier by the Southern system (for which see Locobase 44). Grate area increased because Lima added 12" to the grate's width. The biggest change was a more than 20% increase in superheater area through the addition of ten more flues.

The diagram, dated July 12, 1919, gives only the evaporative heating surface. The superheat area is an estimate based on a similar flue count and length on two other Mikados from the same period.

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Class 900/K/Ms (Locobase 16040)

Data from CNO&TP Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 38, p. 287+ and Vol 43, pp. 31+.

Baldwin's works numbers were 37136-37145 in October 1911 (road 900-903, 907, 921-922), 37164-37166, 37199-37208, 37274-37278 in November (road 923-924, 904-919); 39376-39379, 39415-39420 in February 2013 (road 925-934).

While Baldwin was building large batches of K-class Mikados (Locobase 44), its subsidiary roads were buying smaller amounts. Part of the Southern's Queen & Crescent Route, the railroad's infamous "Rathole Division" in Kentucky and Tennessee demanded as much tractive power as its limited tunnel clearances would permit.

Like the other Ks, these engines were delivered without arch tubes, although the specs state that the firebox's arch could accept them later. By the end of the 'teens, all would be equipped with 32 sq ft (2.95 sq m) of arch tubes and have their boiler pressures set to 180 psi (12.4 bar).

All of the 900s were renumbered by the Southern in 1917.

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Class I/Ks/Ms-3 (Locobase 6095)

Data from the 1917 New Orleans & North Eastern locomotive diagram book supplied in March 2004 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 50, pp. 256+. Works numbers were 41577-41579 in August 1914 and 42743-42744 in December 1915.

These Mikados and the Class H Pacifics delivered in the same year shared everything but driver diameter. Baldwin's specs noted that the rail weight was 75 lb/yard (37.5 kg/metre), maximum grade of 1%, and curves of up to 6 degrees. Such light rail obviously imposed the greatest limitation on power and these engines never grew much. Still, within their dimensions, they had annealed Vanadium cast steel frames, 13" (330 mm) piston valves, 29 sq ft (2.69 sq m) of arch tubes

The Southern first renumbered them 6910-6914, but reclassed them Ms-3 and gave them 6940-6944. Retirements began in November 1946, when the last four were withdrawn. The class leader was sold to the Emory River Railroad in March 1947.

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Class K/Ms (Locobase 44)

Data from Southern Railway diagrams hosted on southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002); Southern Railway Assorted Locomotive Diagrams by Drawing Number supplied by Allen Stanley in May 2005 from his extensive Rail Data Exchange collection; and DeGolyer, Volumes 38, pp. 270+; 42, pp. 296+; 43, pp. 31+; 48, pp. 175+; 50, pp. 307+. See also "Southern Duplex Locomotives,", Railway Mechanical Engineer , Volume 91, No 3 (March 1917), pp. 121-123; and "Duplex Locomotives on the Southern Ry, USA", Locomotive Magazine, Volume 23 (15 July 1917), pp. 131-132. (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 .Also thanks to Larry Walton for his 27 October 2020 email supplying the RR-FallenFlags photograph at []; it led to discoveries of two Southern Railway diagrams showing the layouts on these 2-8-2s and on a 2-10-2. Chris Hohl's 5 May 2022 email corrected the road number range and the boiler pressure.)

Baldwin's works numbers were:

1911

October 37085-37099, 37129-37135

1912

November 38890-38903

December 38943-38947, 38996-38999

1913

January 39000-39001, 39105-39109

1914

April 41337-41346

May 41357-41371

Alco's Richmond works numbers beginning in 1914 were: 54675-54691, 54770-54774.

Although North American railroads are known for their semi-custom attitudes in purchasing similar, but not interchangeable, locomotives from commercial builders, some of the systems bought hundreds of engines built to the same specifications.

These Mikados are a good example of such a program. Between 1911 and 1917, the Southern, its subsidiaries, and the Mobile & Ohio bought K-class superheated locomotives. See the following Locobases for the entries for each railroad:

44 (current entry) Southern 135

13796 Mobile & Ohio 21

16040 CNO&TP 35

16039 Virginia & Southwestern 10

The Southern's buy amounted to 135 of these Mikes from Baldwin and Richmond over six years. The diagram, dated 1911, gives only the evaporative heating surface. The Baldwin spec shows an original calculation for the superheater area of 837 sq ft (77.75 m), but a 21 October 1913 inked correction reports 699 sq ft. Piston valves measured 14" (356 mm) in diameter. All of the Ks were delivered with fireboxes able to accept arch tubes, but not fitted with them. By the end of the 'teens, all would be equipped with 32 sq ft (2.95 sq m) of arch tubes.

Chris Hohl noted the original pressure setting was 175 psi, but the class's boiler pressures rose to 180 psi (12.4 bar) by the end of the 'teens.

Baldwin produced road numbers 4501-4603, 4624-4633 while Richmond supplied 4604-4623 and 4634-4635. All of this class had Walschaert's gear except the following engines, which had Southern gear: 4579-4623, 4634-4635, and 6605.

Beginning in 1915, at least seven of the Southern engines -- 4535-4539 and 4576 -- were fitted with a "tractor" on the tender, essentially converting the tender into a 2-8-0 with 18 x 24" cylinders. In place of the usual two bogie trucks, the design placed the tender tank and bunker on a frame that held the cylinders, Four evenly spaced axles holding 50" (1,270 mm) wheels and a single axle at the front with 30" (762 mm) wheels. (The Erie and Virginian Triplexes used similar tender engines.) Thus equipped, the tender weighed 230,000 lb (104,326 kg( fully loaded and developed 23,100 lb (10,478 kg) starting tractive effort. (4561 received a 2-6-0 tender engine set up.)

Southern diagram (drawing number 25-F-79 dated 31 July 1917 shows the Consolidation layout with 18" x 24" cylinders. 4561's setup used the Mogul running gear originally delivered by Rogers as part of the 1889 locomotive (works number 4190).

The RME report described the result as a "duplex" engine and said the design was a response to congestion on the 68-mile (109.5 km), notoriously adversely graded, single-tracked Saluda grade in western North Carolina. In service, the duplex could move 30% more tons per train than could its non-duplex duplicate. A moment's thought will show that as the boiler and grate weren't enlarged, this bonus had limited duration before the whole assembly ran out of puff.

This isn't to say the Southern oblivious to the demand side's problems. They reduced the Mike's cylinder diameters by an inch to 26" (660 mm). The fireboxes were fitted with brick arches and a feed water heater that used exhausted steam from the air compressor. The result, claimed RME, did not "overtax the Mikado boiler to any great extent."

Locobase 84 refers to a photograph of Ss class 2-10-2 5046 showing the tractor engine in a 2-6-2 wheel arrangement under the tender.

Another problem, which to a lesser extent also affected Beyer-Garratt locomotives, was that as the tender used up its water and coal, its factor of adhesion dropped considerably with greater slipping and loss of traction. It's also not clear to Locobase how steam admission was coordinated between the large cylinders forward and the smaller cylinders behind. As might be expected, the tender tractors were removed in a few years.

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Class Ms-1 (USRA) (Locobase 1428)

Data from tables and diagram in 1930 Locomotive Cyclopedia, SRY 1- 1926 List & Description of Locomotives supplied in April 2004 and SRY 5 - 1929 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange

Southern's USRA light Mikes (Locobase 40) came as a 25-engine batch from Schenectady in 1918; these engines used Walschaert valve gear. Works numbers were 59615-59629 for the Southern itself and 59630-59639 designated for the Cincinnati, New Orleans & Texas Pacific.

So successful was this standard design that the Southern ordered another 45 from Alco-Richmond in 1922-1923. Richmond supplied 63425-63434 and 63553-63567 to the CNO & TP in 1922 and 64842-64851 to the Southern in 1923. These all worked Southern valve gear.

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Class Ms-4 (Locobase 36)

Data from table and diagram in 1930 Locomotive Cyclopedia and

southern.railfan.net/images/archive/southern/steam_loco_diagrams (viewed September 2002). See also DeGolyer, Volume 80, pp. 706+. (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 .)

These were the USRA Heavy Mikado (Locobase 41) designs with enhancements. Firebox heating surface area included 49 sq ft (4.55 sq m) in the combustion chamber and 28 sq ft (2.6 sq m) in arch tubes. Fourteen inch (356 mm) piston valves admitted steam to the cylinders. Water was pre-heated by feed water heaters from Elesco, Worthington, and Coffin.

Used in fast freight (and occasional passenger) service through World War II.

4800-4839 Richmond 1923 (works numbers 64802-64841)

4840-4884 Alco 1924, 1926 (works numbers 66034-66879) with Baker valve gear

4885-4914 Baldwin 1928 (works numbers 60392-60442) with Walschaerts gear

115 total;

51 others on the CNO&TP (Richmond, 1926, works numbers 66834-66851, road #s 6320-6337) -- see Locobase 6485; Baldwin, 1928, works numbers 60450-60494, road #s 6350-6374) and Alabama Great Southern (Richmond, 1926, works numbers 66852-66859, road #s 6622-6629).

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Class Ms-4 (Locobase 6485)

Data from Allen Stanley's collection of locomotive diagram books. This class was shown on a diagram dated May 21, 1943. Works numbers were 66834-66851.

See Locobase 36 for the baseline Ms-4. This set of 18 (and most likely the 25 Baldwins delivered two years later) had fewer tubes and flues that were 2 feet longer each. To distribute the steam, the design was well-served by 16"-diameter piston valves with 7 inches of travel. A Duplex stoker and Elesco feedwater heater (mounted in its characteristic cylinder over the head light) were additional refinements.

According to Dale Roberts and Bill Schafer in Drury (1993), the Ms-4s in general were the standard freight engine all through the Southern system and would occasionally stand in for a passenger engine. The class was retired in 1952-1950.

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Class Ms-6 - 57" (Locobase 11084)

Data from table and diagram in SRY 5 - 1943 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Four of the Ss-1 Santa Fes (see Locobase 1427) -- 5205, 5227, 5244, 5228 -- were truncated in 1929-1931 to create low-drivered Mikados. They retained their original frames, but and apparently the same boilers (at least the same tube and flue counts - which were shared by the Ms-4 class described in Locobase 36), but the boilers at least were cut down by 5 1/2 feet.

This was part of a larger conversion program that was interrupted by the impact of the Depression on traffic volume and revenue. The 4 Ms-6 engines remained in service until 1952.