Great Northern 4-6-2 "Pacific" Locomotives in the USA

Class H-1 (Locobase 8822)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 38894-38899 in September 1905.

Among the first Pacifics to go into service in North America, these passenger engines had slide valves and saturated boilers in front of their Belpaire fireboxes. They had a relatively long stroke, but otherwise sat in the middle of 4-6-2s delivered with saturated boilers.

As far as Locobase can tell, these were never superheated and all were scrapped in 1931.

Class H-2 (Locobase 8819)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 29, pp. 14+ and Volume 30, pp. 14+. Roster information from [], a website authored by Ben Ringnalda.

Baldwin builders' numbers comprised:

28136, 28146, 28157-28159, 28188-89, 28203, 28207, 28229-28230, 28239-40 in May 1906; 28309, 28316-28318, 28377-78 in June; 28523 in July; and

31211-31214, 31276-77, 31301-31303, 31332-33, 31350-51, 31415, 31448 in July 1907.

The most numerous class of Pacifics to go into service on the GN, these had saturated boilers, slide valves, and Belpaire fireboxes as well as relatively long strokes for passenger engines. Baldwin's specification sheet noted a relatively moderate curve limitation of 10 deg.

The 1425 was delivered as a trial horse for the Schmidt superheater. Like the later superheated H-4s (Locobase 146), the boiler had 160 2 1/4" small tubes and 32 l of the 5 1/2" superheater flues and was fitted with 25 1/4" cylinders.

For some reason, although most were converted to H-3 or superheated in the early teens, 10 operated into the 1930s in their original configuration. By then, their boilers had 288 tubes, were pressed to 185 psi, and had 245 sq ft of direct heating surface.

Locobases 8820-8821 show the two main variants of superheated upgrades.

Class H-2-S/H-3-S - 2 " tubes (Locobase 8821)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 8819 shows the original H-2 Pacifics. In the early teens, most were superheated and supplied with 12" piston valves. Locobase 8820 describes the engines that had the less-drastic modification. The larger number received a new boiler to go with its Belpaire firebox, one in which the 2 1/4" tubes of the original were replaced by a larger number of 2" tubes.

In the 1920s, some were upgraded to H-3-S with a new boiler of similar dimensions in which the working pressure was raised to 210 psi. This resulted in a tractive effort of 42,900 lb.

Class H-2-S/H-3-S - 2 1/4" tubes (Locobase 8820)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 8819 shows the original configuration of the GN's H-2 Pacifics. For most of them, it was a layout with a short life. In the early teens, most were superheated and Heron 8 1/2" (216 mm) piston valves were installed in a universal steam chest. Later, almost all of the engines later received 12" (305 mm) piston valves.

This variant retained the 2 1/4" tubes ahead of their Belpaire fireboxes, but reduced the number by 122 when the shops added 30 flues. In the 1920s, some were upgraded to H-3-S with a new boiler of similar dimensions in which the working pressure was raised to 210 psi. This resulted in a tractive effort of 42,900 lb.

Class H-4 - BLW as delivered (Locobase 146)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange and DeGolyer, Volume 34, pp. 26+. See also "Passenger Locomotives for the Great Northern", Railway Age Gazette, Volume 57, No 23 (14 December 1914), pp. 1049-1050. (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 .) Works numbers were 33312-33314, 33330-33332, 33343-33346, 33350-33351, 33359-33364, 33380-33381 in April 1909.

Among the first Pacifics to be delivered with superheaters, the Baldwin design betrays the industry's uncertainty about the best way to use the by-then clear benefits of hotter, drier steam. The H-4s were delivered with an unusually low boiler pressure setting, most likely to take advantage of the lesser strain on components that the more potent superheated steam appeared to allow.

Soon, however, the relatively weak thrust from these pistons led to a new tradeoff between boiler pressure and cylinder volume. Locobase 16276 shows the substantial makeover applied by the GN shops.

The 1913 Lima batch (Locobase 3173) adopted much higher boiler pressure (210 psi/14.5 bar), but smaller 23 1/2" (597 mm) cylinders to retain a good factor of adhesion. These were served by 12" (305 mm) piston valves. If they hadn't been modified by then, Baldwin's locomotives followed suit within a year.

RAG's article describes the road over which these engines ran, noting that one 129-mile section had a maximum grade of 1% and that the Pacifics averaged 30 mph (48 kph) with 11-12 cars over that section..

Class H-4 - Lima (Locobase 3173)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. and DeGolyer, Volume 34, pp. 26+. See also "Passenger Locomotives for the Great Northern", Railway Age Gazette, Volume 57, No 23 (14 December 1914), pp. 1049-1050. Works numbers were 1339-1363 in 1914.

These follow-on locomotives from Lima had slightly less evaporative heating surface, slightly more superheater than the Baldwins of 1909 (Locobase 146). Lima's aspiration to enter the lists against Baldwin and Alco for main-line orders took a big step forward with this order. It was the first for the company to include as many as 25 locomotives in one purchase.

Class H-4 -BLW - 23 1/2" cylinders (Locobase 16276)

Data from GN 1-1929 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

When the Great Northern first acquired the 20 Baldwin Pacifics in 1909 (Locobase 146), they deliberately set the boiler at a low pressure (150 psi) to reduce maintenance. After the Lima batch arrived in 1913 with higher boiler pressure settings and smaller-diameter cylinders, the GN eventually modified the Baldwins to similar, but not quite identical, specifications. The Baldwins had five more small tubes, lower boiler pressure setting than the Limas but 35 psi (2.41 bar) higher than the originals.

Either at the time of this upgrade or a later one, ten--1441-1442, 1450, 1452-1453, 1455, 1457-1459--of the class converted to oil burning and that version is shown in the specs. Most of this subgroup also acquired an American Security company brick arch with four arch tubes that contributed 31 sq ft (2.88 sq m) to the firebox heating surface area, and a "No 3" Worthington feed water heater. In the 1920s, 1447-1448, 1454, 1456 received Delta trailing trucks fitted with boosters that developed 11,000 lb (4,990 kg) tractive effort.

Before their retirements in the early 1950s, the boiler's working pressure had been reset again to 210 psi .bar) and the engine put 176,500 lb (80,059 kg) on the drivers(divided as equally as possible into axle loadings of 58,833 lb/26,686 kg) and 273,760 lb (124,176 kg) on the twelve fully loaded axles. The oil-burners' tenders then carried 4,500 US gallons (17,033 litres) of oil fuel and weighed 188,400 lb (85,457 kg) fully loaded

Class H-5-S (Locobase 6450)

Data from GN locomotive diagram found on Ben Ringnalda's [] (viewed 8 Jan 2005). Many thanks to Max Magliaro who wrote Wes Barris of steamlocomotive.com concerning an unwonted lumping of the H-5-S and H-7-S classes. His questions and research resulted in Locobase splitting the record into two entries. H-7-S is found in Locobase 14987.

A long article -- [] (viewed 11 July 2005) -- describes both the E-14 and the H-5 Pacific that resulted from a substantial rebuild. It is based on a reference sheet originally drafted by Doug Bemrich for the GNR Historical Society and based on research by Bemrich and Larry Obermeyer, Jr. See Locobase 8815 for a similar rebuild of J-1 & J-2 Prairies to the H-6 Pacific class.

This class was rebuilt the 1909 batch of E-14 Ten-wheelers from Baldwin to match approximately the capacity of the H-4 Pacifics (See Locobase 146 & 3173) that the Great Northern had bought before World War I. As noted in Locobases 6682 and 8844, the E-14s were produced in two quite different sizes that were the basis of each of the two Pacific rebuilds.

Compared to the earlier E-14s, the rebuilds had a much longer wheelbase under a boiler whose tubes ran 4 feet (1,219 mm) longer and noticeably higher axle loadings. (The latter improved the factor of adhesion.) The H-5-S retained the evenly spaced drivers (7 feet/2,134 mm between each two axles) and firebox dimensions as well as the power dimensions of the 1909 E-14s.

H-5-S Belpaire firebox heating surface area varied depending on fuel. Five coal burners included 31 sq ft (2.9 sq m) of arch tubes in an American Brick Arch installation. (These were road numbers 1352, 1354, 1356-1357, 1373.) The combustion chamber's area was included in the overall figure for firebox heating surface. This quintet's tenders held 19 tons (17.3 metric tons).

The oil burners were 1350-1351, 1353, 1355, 1358-1372, 1374. Of these 1350-1351 had 160 tubes, which raised tube heating surface area to 2,932 sq ft (272.4 sq m) and total heating surface area to 3,179 sq ft (295.3 sq m). Four--1350-1351, 1358-1359--also had Worthington feedwater heaters.

All H-5-S had piston valves measuring 12" (305 mm) in diameter. A Sellers Exhaust Steam Injector was part of the package.

The last 10 -- modfied in 1926-1927 and designated H-7-S -- sported a trailing-truck booster that contributed 11,700 lb to starting tractive effort. They are discussed in Locobase 14987.

The article mentioned above thoroughly describes all of the modifications and is strongly recommended. Suffice it here to say that every significant steam-producing dimension, area, or volume was enhanced beyond not only the E-14, but also the H-4 Pacific. Direct heating surface percentage of total EHS, superheater percentage of total heating surface, ratio of heating surface to cylinder volume, efficiency and maintainability of the superheater. In sum, the effort proved well worth the cost.

The rebuilding program lasted most of the 1920s. New numbers were consecutive, but did not line up with the E-14s that preceded them. After the first ten had been rebuilt in 1921-1925, the GN renumbered the class to make room for all 25.

The reconstruction proved of enduring value and very few significant changes were made to the class over the next 30 or so years of service. 1351 wrecked on 24 July 1941.

In a 20 February 2013 email to Locobase, Max Magliaro noted that the 1378 was leased by the GN in 1942 to the Spokane, Portland & Seattle as their 626. The railroad later bought the 626 outright. It was the only SP&S to use a Vanderbilt tender.

The others were sold for scrap beginning in 1950 (1), 1951 (2), 1952 (8), 1953 (7), 1954 (2), and 1955 (3). One of the class -- 1355 - was preserved as an outdoor exhibit until its restoration began at the turn of the 21st Century.

Class H-6 (Locobase 8815)

Data from GN 1 -1929 and GN 4 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Turned out the Great Northern wasn't finished with some of the class of J-2 Prairies (Locobase 8533). Beginning in 1923, 15 were converted to Pacifics along the same lines as the H-5 conversions from E-14 Ten-wheelers (see Locobase 6450). The grate area in the Belpaire firebox stayed the same, although total direct heating surface increased, and the cylinders retained their long stroke. Piston valves measured 12" (305 mm) in diameter.

The boilers grew through a further reduction in tube count in favor of two more flues and in the lengthening of all tubes and flues by 2 1/2 feet. Working pressure rose to 200 psi and the axle loading climbed to over 28 tons.

More than half the class burned oil instead of coal. 1710-1717 trailed tenders carrying 4,500 US gallons (17,034 litres) along with the 8,000 gallons of water. These were the former J-2 Prairies 1634, 1572, 1616, 1552, 1569, 1619, 1598, 1525. Two more--1721-1722, former 1519, 1525--joined them later. The other five (ex-1517, 1553, 1528, 1612, 1570), were renumbered 1718-1720 and 1723-1724, respectively.

Class H-7-S (Locobase 14987)

Data from GN 1 - 1929 locomotive diagram supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Many thanks to Max Magliaro who wrote Wes Barris of steamlocomotive.com concerning an unwonted lumping of the H-5-S and H-7-S classes. His questions and research resulted in Locobase splitting the record into entries. H-5-S is found in Locobase 6450.

Like the H-5-S, the H-7-S was a Pacific design built by Great Northern from large E-14 Ten-wheelers. The railroad's shops built two distinct Pacifics out of those earlier engines, each class based on a different Baldwin batch. The H-7-S had unevenly spaced drivers (6 1/2 feet/1,981 mm between axles 1 and 2 and 7 feet/2,134 mm between axles 2 and 3) and a longer firebox with more grate area than the H-5-S. These features were part of the 1910 order of Ten-wheelers and together with the power dimensions formed the basis of the 1926 makeover. Compared to the original Ten-wheelers, the rebuilds had a longer wheelbase and noticeably higher axle loading. (The latter improved the factor of adhesion.).

In half of the H-7-S engines, those that burned coal (1377-1381), the Belpaire firebox's heating surface area included 28 sq ft (2.9 sq m) of arch tubes in an American Brick Arch installation. The small combustion chamber's area was included in the overall figure for firebox heating surface. The oil burners (1375-1376, 1382-1384) did not have a brick arch and their tenders held 5,219 US gallons (19,754 litres). Total heating surface area 3,157 sq ft (299.3 sq m).

All ten H-7-S had 12" (305 mm) piston valves, Delta trailing trucks, and an Elesco exhaust steam injector.

Compared to the E-14 as well as the H-4 Pacific, the H-7 rebuilds, like their more numerous H-5s, gained in most areas. Direct heating surface percentage of total EHS, superheater percentage of total heating surface, ratio of heating surface to cylinder volume, efficiency and maintainability of the superheater. In sum, the effort proved well worth the cost.

The reconstruction proved of enduring value and very few significant changes were made to the class over the next 30 or so years of service.

The H-7-S were rebuilt in a second phase that began in 1926. New numbers were consecutive, but did not line up with the E-14s that preceded them.

In a 20 February 2013 email to Locobase, Max Magliaro noted that the 1378 was leased by the GN in 1942 to the Spokane, Portland & Seattle as their 626. The railroad later bought the 626 outright. It was the only SP&S to use a Vanderbilt tender.

Class H5 (Locobase 8852)

Data from GN 1916 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

This is a mystery engine, possibly a one-only conversion of an H-2. (Other H-5s were later conversions of E-14 Ten-wheelers.) The square cylinder dimensions enclosed a large volume, a spacious Belpaire firebox hosted a broad grate, and both tube sizes were substantial as well.