Class A-24 (Locobase 4121)

Data from Railroad Gazette (13 December 1901) and more fully on 26 April of the same year,

These were "Chatauqua" engines, which was a then-common alternative to "Atlantic" RG noted that the sextet was "doing very good work, sometimes hauling passenger trains of 14 cars on a quick schedule, with no difficulty in feeding the boiler sufficiently with one No. 9 injector. They have made a record for being 'smart' and economical."

RG gives total heating surface as 2,806 sq ft and the grate area as 55.70 sq ft. The total engine weight was given as 167,000 lb. The 1903 Rock Island locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange shows different heating surface dimensions from the RG article and they are the ones used in the specifications.

Builder info from B.Rumary, 25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND and Jeremy Lambert as supplied by Allen Stanley in March 2004. Works #3766 in February 1901, 3825 (April 1901), 3911-3914 (July 1901).

NB: Tube length is an estimate based on the calculation of tube surface area by subtracting reported firebox heating surface from reported total evaporative heating surface.

Class A-24 (Locobase 5358)

Data from "Baldwin Balanced Compound for the CRI & P", Railway and Locomotive Engineering, Vol 18, No 11 (November 1905), p. 513, and DeGolyer, Volumes 27, p. 285 and 29, p. 42. (Thanks to Chris Hohl for his 8 August 2016 email reporting the valve gear.) Works numbers were 26474, 26511 in September 1905, 28875-28876 in August 1906 and 28930-28931, 28937, 29011 in September.

Drury (1993) says that the first pair of this balanced-compound class -- 1048-1049 -- arrived in 1905. Each of two piston valves of 15" (381 mm) diameter were cast in the valley between the inside and outside cylinders and supplied live steam to the inside HP cylinder and HP exhausted steam to the outside LP cylinder.

A general note in the 1905 specs advised the builder that "Special attention to be paid to fitting radial stays, to strength of frame and to counterbalance of wheels." (In truth, this admonition could be applied to any steam locomotive ...). Details of the three Consolidated safety valve settings reflect an attempt to reduce noise levels as well as a subtle indicator of pressure, requiring the 210 lb valve setting to be "muffled", but the 215 and 220 to be "open".

The Rock Island ordered another six of the design on 15 January 1906.

Baldwin estimated the tender weight as 161,000 lb (73,028 kg); the actual weight is shown in the Locobase specs.

The design met the requirements satisfactorily enough to lead to the purchase of six more (1042-1047) in 1906 (Locobase 5359).

By the end of the Nineteen teens, however, the Rock Island decided to simplify and superheat the class; the result is shown in Locobase 8355.

Class A-24 - 1042 - superheated (Locobase 8355)

Data from RI 1 - 1942 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Delivered as compounds (Locobase 5358), this class was reworked in 1919-1920 to include a superheater. There was some loss of total evaporative heating surface, but the drier steam more than made up for the deficiency. The firebox heating surface area included 31/4 sq ft of arch tubes, which may have been included in the original layout.

Notwithstanding the upgrade, the Atlantic arrangement was too limited in its applicability and this class was withdrawn in 1935-1942.

Class A-25 (Locobase 5359)

Data from 1903 Rock Island locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange credits them with "Alco" superheater. See also "Report of the Committee on Superheaters--42nd Annual Conference, Master Mechanics' Association", American Engineer and Railroad Journal, Volume 83, No. 6 (June 1909), pp. 281-282. Works numbers were 28148-28149 in April 1905.

The Rock established itself as an early North American investigator of the benefits of superheating steam when it ordered the last two locomotives in the batch of ten engines described in Locobase 16229 delivered with Alco superheaters and 12" (305 mm) piston valves instead of the earlier octet's slide valves. (The road also ordered some Pacifics with superheaters.)

The railroad tested the pair against similar designs with saturated boilers and locomotive superintendent reported that water savings in the 1019 averaged 16%, while very little coal economy was recorded. Seley underscored the trial nature of this purchase, saying that they were "put in service to ascertain their ability to do business without causing train delays or unduly increasing maintenance expense due to the superheater features. It was felt that these were matters of detail that should be worked out before any records or tests for economies were necessary or advisable. We had a number of difficulties of one kind and another, but through them all the advantages due to the superheater features were sufficiently apparent to warrant the effort to overcome them, which we have now done in large measure and feel confident that the showing here made is an honest, consistent one."

The Alco superheater was a low-superheat design that did not gain much of a following.

Like the road's other Atlantics, this class left service only in 1935-1937.

Drury (1993) notes that eight of these were delivered with slide valves, two with piston valves. The specs probably refer to the piston-valved pair.

Like the road's other Atlantics, this class left service only in 1935-1937.

Class A-25 (Locobase 16229)

Data from 1903 Rock Island locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 28140-28147 in April 1905.

At the same time Baldwin supplied some of its balanced compounds (Locobase 5358), Alco's Schenectady Works delivered some of its own Atlantics equipped for simple expansion. The eight shown in this entry had saturated boilers and slide valves; two others with a low-temperature superheater are described in Locobase 5359.

Like the road's other Atlantics, this class left service only in 1935-1937.

Class A-25 - schmidt superheater (Locobase 16230)

Data from RI to 1951 locomotive diagram combination of books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 16229 describes the simple-expansion Atlantics supplied by Schenectady in 1905 and 5358 covers the two of that class delivered with Alco low-temperature superheaters. Only the two with Alco superheaters were updated with Schmidt superheaters, possibly because the class's short boilers couldn't offer enough of a difference from a saturated one.

Like the road's other Atlantics, this class left service in 1935-1937.

Class A-29 (Locobase 107)

Data from "2264. Rock Island 1040 Class Passenger Locomotives," Brotherhood of Locomotive Firemen & Enginemen's Magazine, Volume 56 , No 3 (March 1914), pp. 344-346. See also Locomotive Dictionary, Fourth Edition (New York: Simmons-Boardman, 1916) Figure 122 for elevation and cross-section drawings of this engine; and "Valves", Locomotive Cyclopedia of American Practice, Sixth Edition (New York: Simmons-Boardman, 1922) p. 481, Figure 853 for a cutaway of the valve gear. Also, George H Drury, Guide to North American Steam Locomotives-Revised Edition (Waukesha, WI: Kalmbach Publishing, 2015), p.142. (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 .)

Balanced simple engines with two cylinders inside and two outside, all driving the leading set of drivers. The four-cylinder, line-abreast layout on a rigid wheelbase was rare in the US, but used often in Britain through the first three decades of the Twentieth Century. These two engines stayed in service until the mid-1930s.

Figure 853 from the Locomotive Cyclopedia, shows a cutaway of the design. The 10" (254 mm) piston valves rode in tandem in a single casting for the pairs of cylinders on each side. Steam entered through the center of the valve and was routed to inner ports, which served the outside cylinders, and to outer ports, which supplied the inside ones. Thus, steam would be entering the back of (say) the inner cylinder at the same time it was entering the front of the outer cylinder. This was a rare setup, which suggests that the mechanism was hard to "tune" or simply too complicated easily to maintain.

The BFLE response for information about these locomotivs reported that the 1040 used 13.3% less water than the railroad's balanced compound Atlantics and 11.7% less than the two-cylinder simple. Fuel savings of 6.7% over the compound and 16.9% over the simple seemed equally dramatic.

Engineers claimed that "it was necessary to ease off across the prairies, as they had never seen a locomotive that could run so fast and do it so easily." Drury's review of Rock Island power noted that in a four-cylinder simple layout, the "moving parts were in balance and only small counterbalances were necessary on the drivers."

According to a later Rock Island locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange, by 1937 these locomotives had larger superheaters with 582 sq ft of surface area.

1040 was scrapped in September 1936 with 1041 following in March 1937.

Class Chatauqua (Locobase 3876)

Data from Railroad Gazette (30 November 1900).

Builder info from B.Rumary, 25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND and Jeremy Lambert as supplied by Allen Stanley in March 2004. Works #3642, 3668-3669. Also see RI 11 - 1903 Locomotive Classification and Diagrams supplied by Stanley in May 2005.

RG describes these powerful Chautauquas as "having the general characteristics of the Atlantic type." Clearly, the latter name was more widely used. They had Player-Belpaire boilers and 10" piston valves.

Angus Sinclair, writing in the January 1901 Locomotive & Railway Engineering, made a reasonable prediction:"We think that this type of engine is destined to become very popular for the service for which this one was built, because it enables the designers to put in a very large firebox, and to make it deep enough so that it can be fired with sufficient

depth of combustible to ensure a high firebox temperature."

The B, CR & N was absorbed by its controlling railroad -- the Chicago, Rock Island and Pacific in 1903, at which point these three Atlantics became 1001, 1003, 1002, respectively. They carried on until the 1930s.