Class Q-1 (Locobase 1037)

Data from B & O Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive collection.

140 engines delivered in 1911. Q-1s (4000-4149) were produced in January-November 1911 and had works numbers 35911-35924, 36010-36030, 36209-36213, 36407-36410, 36418-36420, 36452-36455, 36494-36497, 36528-36538, 36597-36613, 36619-36623, 36630-36633, 36663-36668, 36672-36681, 36686, 36692-36693, 36706-36710, 36728-36739, 36777-36782, 36789-36794, 36836-36837, 36841-36848. (10 Q-1a were superheated variants with the same cylinder volume.)

Beginning only a few years after their introduction, the class was superheated and modified as Class Q-1aa; see Locobase 3096. Others were converted to P-1c Pacifics; see Locobase 9610.

Last Q-1 retired in 1956 (although the last Q-1c left service in 1941). Q-1b (4150-4219 - see Locobase 9613)) and Q-1c (4220-4319 - Locobase 9614) had 26" x 32" cylinders and a 190-psi working pressure.

Locobase needs to confirm that the two classes shared the same boiler -- a design economy pursued by the Pennsylvania with great success in its K-4 and L-1 designs of 3 years later. The information provided in the diagrams suggests, however, that the Q-1 was very short of direct heating surface.

Class Q-1B / Q-1B (Locobase 9613)

Data from B & O to 1954 Asstd Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive collection. Baldwin works numbers: 37102-37106, 37181-37185, 38079-38080, 38120-38129, 38170-38175, 38211-38215, 38232-38239, 38290-38292, 38339-38340, 38364, 38412-38414, 38419-38420, 38482-38489 - produced from October 1911 to October 1912.

Although the first 150 of the Q-1 locomotives had saturated boilers, Baldwin and the B & O soon switched to a superheated design that would serve as standard equipment for the road's 2-8-2s as well as its Pacifics. Adding 28 sq ft of arch tubes to the firebox beginning in 1916 fortified a rather anemic direct heating surface area and caused a change of designation to Q-1BA.

Hundreds of B & O Mikados and Pacifics were built or reworked to this common baseline, which included not only the firebox and boiler, but also the cylinders and 14" piston valves. The Q-1C, which is shown separately in Locobase 9614, was delivered with arch tubes in the firebox, but was otherwise identical.

Class Q-1C (Locobase 9614)

Data from B & O to 1954 Asstd Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive collection. Baldwin works numbers: 40065-40069, 40087-40089, 40107-40108, 40145-40163, 40192-40200, 40243-40249, 40287-40290, 40326-40334, 40349-40356, 40382-40390, 40437-40440, 40513-40524, 40567-40580, 40597-40604, 40645-40646, 40685-40691 - produced June 1913 to September 1913.

As noted in Locobase 9613, the boiler, firebox, and cylinders of the superheated Q-1 Mikes appeared in virtually of the B & O's pre-World War I Mikados and Pacifics or was retrofitted to those classes in the 1920s. The Q-1C class shown here was delivered with everything in place, including the 28 sq ft of arch tubes that all such locomotive would eventually use.

Unlike many other railroads, however, the B & O didn't add other heat-augmenting devices like thermic syphons to these earlier engines.

Class Q-1aa (Locobase 3096)

As described in Railway Age (11 July 1931), these are the superheated version of the original Q-1 (Locobase 1037), having been rebuilt with larger-bore cylinders and a larger firebox in the late 1920s. Given the reduction in the length of the tubes, they may also have been given a combustion chamber. The railroad also cut the working boiler pressure to 195 psi. Steam admission came through 14" piston valves.

The variant shown in the specs had the larger of the two superheater installations. The other boiler had 218 2 1/4" small tubes and 34 5 1/2" flues; total EHS came to 3,962 sq ft and superheater surface area totalled 811 sq ft. Firebox heating surface for both versions was the same and included 26 sq ft of arch tubes. Many of these were later converted to Pacific passenger power as P-1c; see Locobase 9610.

The large class was obviously a common 2-8-2 type on the B & O and served until the end of steam.

Class Q-2 (Locobase 2081)

Data from B & O 1954 Asstd Loco Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Alvin F Staufer & Lawrence W Sagle, B & O Power (1964).

One of the few Lima-built classes on the B&O, once the CI&W came under the bigger railroad's control. Renumbered in 1927 as 4162-4169 and ran until 1950.

Class Q-3 (Locobase 1038)

Alvin F Staufer & Lawrence W Sagle, B & O Power (1964). Data from B & O Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive collection.

100 engines delivered in 1918, including the first for the USRA. Compared to the earlier Q-1s, this class had more firebox heating surface.

Last Q-3 retired in 1959.

Class Q-4 (Locobase 941)

Data from Alvin F Staufer's Baltimore & Ohio Steam and Electric Locomotives (Medina, Ohio) supplied by Allen Stanley from his extensive collection May 2005.

Firebox heating surface included 35 sq ft of arch tubes as delivered. Later variations included a semi-water tube firebox in which 29 sq ft of arch tubes added their area to the sheets, troughs, and side tubes of the water-tube box. Others added a tiny combustion chamber that contributed only 6 sq ft. When 3 arch tubes were deducted (leaving 14 sq ft) and 70 sq ft of thermic syphons were added, the total firebox heating surface came to 309 sq ft.

Valve gear varied. Most of the class had Baker gear, but the quintet numbered 4445-4449 used a "modified Walschaert".

135 engines delivered in 1920-1923. May have shared components with better-known Big Six 2-10-2. These locomotives were rated for passenger service. Last Q-4 retired in 1959.

Class QoddA (Locobase 9615)

Data from B & O to 1954 Asstd Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive collection.

Probably as an experiment, the B & O took 2 of its numerous E-27 class of 2-8-0s (Locobase 2885) and converted them into these superheated Mikados. Given that the boiler was lengthened, the driver and cylinder diameters increased, valve gear changes, superheater added -- about the only component retained was the relatively small firebox.

Another sign of experimentation was the slightly different rear frame lengths of the two engines. 4160's engine length was as shown in the specs; 4161's measured 35 ft 3 in. In any case, this 8-coupled Odd Couple operated in freight service until 1949.

Class Z / Q-10 (Locobase 2066)

Data from BR&P 11 - 1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Alvin F Staufer & Lawrence W Sagle, B & O Power (1964).

The only BR&P Mikados, these were broken into 4 subclasses by the B&O in 1932 and renumbered 4700-4747. Q-10 (400-406), Q-10a (407-437), Q-10b 438-446), and Q-10c (447). These basic freight engines soldiered on until the end of steam in 1954.