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Chicago and North Western Z class

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Class of 251 American 2-8-0 locomotives
C&NW class Z
Omaha Road class Z
C&NW 1455, the first of the class Z (Alco 46607 of 1909)
Type and origin
Power typeSteam
Builder
Serial numbersee table
Build date1909–1913
Total produced251
Specifications
Configuration:
 • Whyte2-8-0
 • UIC1′D n2, later 1′D h2
Gauge4 ft 8+1⁄2 in (1,435 mm)
Driver dia.61 in (1.549 m)
Wheelbase36 ft 5 in (11 m)
Loco weight235,000–243,500 pounds (106,600–110,400 kg)
Firebox:
 • Grate area52.68 sq ft (4.894 m) (108 in × 70+1⁄4 in or 2.743 m × 1.784 m)
Boiler:
 • Diameter81+1⁄2 in (2.070 m)
Boiler pressure170 lbf/in (1.17 MPa)
CylindersTwo, outside
Cylinder size25 in × 32 in (635 mm × 813 mm)
Valve gearWalschaerts or Baker
Valve type14 in (360 mm) piston valves
Valve travel6 in (150 mm)
Performance figures
Tractive effort47,500 lbf (211.29 kN)
Career
Operators
Number in class
  • CNW: 249
  • CMO: 2
Numbers
  • CNW: 1455–1494, 1700–1910
  • CMO: 219–220
DispositionAll scrapped

The Chicago and North Western Railway class Z (and Omaha Road class Z) was a class of 251 American 2-8-0 locomotives. They were built between 1909 and 1913, when production switched to the larger class J 2-8-2 locomotives. The class letter spawned their nickname amongst C&NW and Omaha Road crews: "Zulu".

Design

The locomotives has boiler pressed to 170 pounds per square inch (1.2 MPa) feeding steam to two cylinders that had a 25-inch (640 mm) bore and a 32-inch (810 mm) stroke. These were connected to 61-inch (1,500 mm) driving wheels buy Walschaerts valve gear, although the last 47 were built with Baker valve gear. They had 14-inch (360 mm) piston valves with 6 inches (150 mm) travel. The firebox was of the radial-stay pattern, 108 inches (2,700 mm) deep by 70+1⁄4 inches (1,780 mm) wide. The resulting 52.68 square feet (4.894 m) was 14 per cent larger than the class R-1.

Construction

Apart from a batch of 25 built by the Baldwin Locomotive Works, all the locomotives were built by the American Locomotive Company at their Schenectady plant. Baldwin classified their locomotives as 10-48-E

Table of orders and numbers
Year Quantity Manufacturer Serial numbers C&NW numbers Notes
1909 40 Alco 46607–635/637/636/638–646 1455–1494
1910 25 Baldwin 34991, 35015–022/060–065/101–106/144–145/223–224 1700–1724
1910 26 Alco 47845–47870 1725–1750
1910 27 Alco 49035–49061 1751–1777
1911 23 Alco 49062–49084 1778–1800
1911 20 Alco 50494–50513 1801–1820
1912 45 Alco 50849–50893 1821–1865
1913 45 Alco 53047–53091 1866–1910
1913 2 Alco 53092–53093 219–220 Omaha Road

Service

On the C&NW, they were used system-wide on freight trains, and were the principle freight-hauling locomotive on the railway until the arrival of the class J Mikados. The extra power over the existing freight locomotives enabled running 75-car trains; unfortunately, older wooden-framed freight cars could not stand the punishment and a large number of "bad-ordered" cars required repairs. The Omaha Road used its pair, like all its 2-8-0s, in switching, transfer and helper service. They had in fact been delivered a week after the Omaha Road's first class J 2-8-2 locomotives.

When new all had been built as hand-fired coal-burning locomotives. The large grates were tricky to fire and several firemen resigned as a result. At least 17 were fitted-up for oil-firing for use in Wyoming, where fuel oil was readily available. Twelve others received mechanical stokers during World War II.

In 1942, several locomotives were leased out to other operators; by war's end, these had either been purchased or returned. Sales included five to American Smelting and Refining Company (ASRCo), five to the Seaboard Air Line Railroad (SAL), two to the St. Louis Southwestern Railway (Cotton Belt or SSW), 25 to the Ferrocarriles Nacionales de México (NdeM) directly, and another seven via a dealer. They also later acquired ASRCo's five.

The first retirement was in 1936; fifty were still in service in mid-1948. The Omaha Road retired both of its Zulus in June 1956.

Table of pre-1948 scrappings
Year Quantity in
service at
start of year
Quantity
scrapped
Numbers Notes
1936 251 1 1750
1937 250 5 1719/30/51/86, 1827
1938 245 4 1488, 1721, 1893, 1908
1939 241 2 1481, 1720
1940 239 42 1462/74/76/82,
1704/08/09/11/14/22/23/26–28/32/40/54/55/65/66/70/72/74/83/91/95,
1808–10/15/21/30/33/47/56/62/65/67/91/92/94,
1903
1941 197 34 1455/59/60/64/65/70/73,
1700/10/31/36/42/60/63/96/98,
1807/12/17/18/24/29/34/40/44/45/54/61/68/71/78/82/86
1900
1942 163 3 1467/94, 1793 scrapped
1942 1717/24/85, 1837/58 to ASRCo 4000–4004; to NdeM 1582–1586
1942 1466/68/69/86, 1790, 1848/97 to NdeM 1550/51/55/52/53/54/56 via dealer
1942 1477, 1725 to Cotton Belt 540–540 (SSW class K-1)
1942 1458/61/87
1702/84/89/99
1820/31/53/60/66/72/74/81/83/88/98
to NdeM 1558–61/69–81/57 (class GR-43)
1943 128 1744/87, 1806/43/59 to SAL 933–937 (class H-2)
1943 1729/46/59/64/77/81/82 to NdeM 1562–1568
1944 116 15 1463/72/75/78,
1718/37/43/56/67/97,
1816/25/36/38/84
1945 101 22 1457/71/85/91/92,
1701/34/38/45/53/68/69/73/92
1835/42/57/63/76
1901/04/05
1946 79 12 1480, 1713/33/47/52/62, 1804/05/77/89/90, 1907
1947 67 17 1456, 1706/12/41/49/57/58/80, 1819/50/51/64/85/96/99, 906/10 1899 became stationary boiler at Chase Roundhouse, Milwaukee
1948 50 0 first half-year only

No locomotives of this class have been preserved.

References

  1. ^ Mailer (2004), p. 139.
  2. ^ Cole (1938), pp. 60–61.
  3. ^ Mailer (2004), p. 302.
  4. Mailer (2004), p. 144.
  5. Mailer (2004), p. 145.
  6. Chicago and North Western Railway (1948), pp. 8, 10–12.
Chicago and North Western Railway steam locomotives
4-2-0
0-4-0
2-4-0
4-4-0
4-4-2
0-6-0
2-6-0
4-6-0
4-6-2
4-6-4
0-8-0
2-8-0
2-8-2
2-8-4
4-8-0
4-8-4
2-10-2
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