Duluth & Iron Range 2-8-2 "Mikado" Locomotives in the USA

Class N (Locobase 7288)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 82005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 46, pp. 289+, and "Mikado and Pacific Locomotives for the Duluth and Iron Range," Railway and Locomotive Engineering, Volume 26, No 8 (August 1913), pp. 280-281. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.).

When the Iron Range went to Mikados a few years after it bought 8its last Consolidations, it didn't pussy-foot. These 2-8-2s ranked with the largest of the 8time, particularly in the grate and firebox areas. The latter included 37.3 sq ft (398.19 sq m) in five American Arch Company tubes. The cylinders received their steam through 15" (381 mm) piston valves. The R&LE report notes that the back equalizing beams were placed diagonally to connect directly with the truck spring links.Other details allowed the removal of cross beams and allowed "ample room" for the ash pan.

Beginning in 1931, the DM&IR significantly modified this quartet; see Locobase 16191.

---

Class N - modified (Locobase 16191)

Data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.).

As noted in Locobase 7288, later DM&IR upgrades begun in 1931 significantly altered the specifications of these locomotives. Tube count decreased by 15 to 273 and firebox heating surface area to the 271 sq ft shown. This wasn't an unusual change. What was not common, however, was to trade tube count for an increasd diameter (from 5 3/8" to 5 1/2") in the flues. Even with the increase in flue diameter, the superheater area decreased by 59 sq ft (5.48 sq m), which suggests either shorter or perhaps thinner superheater elements.

Even tender capacities decreased. In those same upgrades, however, boiler pressure increased by 25 psi (1.72 bar) and adhesion weight showed a 15 1/2 ton increase over the 1913 specification (which was not necessarily its delivered weight). As with the Lima engines shown in Locobase 16190, the original 1913 Baldwins may have had difficulty getting enough steam in the cylinders because the piston valve diameter increased to 16" (406 mm). Still later, both 1300 and 1302 were fitted with Security circulators in the firebox.

Like most of the DM & IR engines, these Mikados remained in service until the road went to diesels in the late 1950s.

---

Class N-1 (Locobase 16190)

Data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.). Lima works numbers were 1311-1312 in December 1913.

Locobase 7288 shows the first four Duluth & Iron Range Mikados delivered by Baldwin in 1913. The Lima pair were only the sixth and seventh Mikes delivered by that Ohio builder. Locobase has not found data for the original configuration, showing here instead the upgrades adopted beginning in 1931.

They were very similar to those installed in the Baldwins (Locobase 16191), but somehow the superheater area reduction was limited to 29 sq ft (2.69 sq m). The original 1913 design may have had difficulty getting enough steam in the cylinders because the piston valve diameter increased to 16" (406 mm). Later, 1305's firebox received Security circulators.

---

Class N-2 (Locobase 7289)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 55, pp. 177+. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.).Works numbers were 43303-43305 in May 1916.

Three years after Baldwin and Lima supplied the Iron Range with its first Mikados (Locobase 7288), Baldwin delivered three more slightly bigger engines. The firebox stayed the same, but the boiler had more tubes and flues, which yielded a higher percentage of superheated heating surface. Steam admission came through 15" (381 mm) piston valves.

Otherwise, there were few differences.

The Mikes went through a makeover at some later stage that seems to involved a new boiler pressed to 200 psi. The boiler's tube count was reduced by sixteen to 288, which reduced the evaporative heating surface area to 4,453 sq ft (413.85 sq m) and two of five arch tubes were also deleted, trimming the firebox heating surface to 268 sq ft (24.9 sq m). The 1951 diagram gives the adhesion weight as a considerable 251,270 lb (113,974 kg) and overall engine weight as 338,320 lb (153,460 kg), which put the factor of adhesion at 3.9.

---

Class N-2/N-3 - updated (Locobase 16192)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.).

The Mikes described in Locobase 7289 and 7290 went through a makeover at some later stage that seems to involved a new boiler pressed to 200 psi. In all six, the boiler's tube count was reduced by sixteen to 288. Two of five arch tubes were also deleted, trimming the firebox heating surface. As with the Baldwins shown in Locobase 16190, reducing the number of tubes in the boiler allowed an increase in flue diameter from 5 3/8" to 5 1/2".

The shops later installed two Nicholson syphons in 1308's firebox while fitting Security circulators in 1306.

---

Class N-3 (Locobase 7290)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 71, pp. 65+. (Many thanks to Chris Hohl for his 27 August 2015 email and spreadsheet spelling out the Baldwin specs for all three orders of D&IR Mikados. It led to the addition of three new entries and revision of 7288-7290.).Works numbers were 56507-56509.

Soon after the First World War, the Iron Range returned to Baldwin for more Mikados. Rather than adopting the USRA Heavy Mikado (Locobase 41) design, the Iron Range accepted a slight rework of the 1916 Mikes they already operated (see Locobase 7289).

A principal reason may have been the need to have smaller drivers than the USRA's 63" and the railroad was quite familiar with the peculiarities of this design. The 1923 trio was delivered with the same tube count as the 1916 engines, but later had the count reduced to 291 resulting in a reduction of the evaporative heating surface to the 4,484 sq ft shown in the specifications.

One difference was the provision of a Superheater Company (Elesco) feed water heater. Steam was admitted to the cylinders through 15" (381 mm) piston valves.

In any case, all of the engines served to the end of steam power on the DM & IR.