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 feeding steam to two cylinders that had a bore and a stroke. These were connected to driving wheels buy Walschaerts valve gear, although the last 47 were built with Baker valve gear. They had piston valves with travel. The firebox was of the radial-stay pattern, deep by wide. The resulting 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 inservice atstart of year Quantityscrapped 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