Last revised: October 5, 2026
By: Adam Burns
The Norfolk & Western’s Class Z was a compound 2-6-6-2, 190 engines numbered 1300–1489, built from 1912 through 1918. Fifteen of them, the Z-1s, came from Alco’s Richmond works with Walschaerts valve gear. The other 175, the Z-1as, came from Richmond, from Baldwin, and from Alco’s Schenectady works, with Baker valve gear. High-pressure cylinders were 22 by 32 inches. Low-pressure cylinders were 35 by 32 inches. The railroad rated the class at 75,830 pounds of tractive effort compound, and 90,996 pounds in simple, at 225 pounds of boiler pressure.
They were the articulated that settled into road service. Five 0-8-8-0s and five 2-8-8-2s had come in 1910, and the 2-6-6-2 is what the railroad then bought in quantity. Ron Rosenberg’s table still shows 116 of them on the roster in 1942 and again in 1944, against an all-time maximum of 190. The last retirement on the diagram record is April 1958. None was saved. The later articulateds are the Class Y 2-8-8-2s and the Class A 2-6-6-4s.
Norfolk & Western 2-6-6-2 No. 1444, the tender lettered Norfolk and Western, in a 1940s yard view. Number 1444 was built by Alco-Schenectady in the 1915–16 group, engines 1420–1449, and the roster at the end of 1942 carries it as a Z-1b. Photographer unknown.
On this page: At a glance · 1910, and a borrowed 2-6-6-2 · One hundred ninety engines · The 1929 diagram · Three tenders · On the road in 1913 · The Z-1b · One simple engine · Roster · Who left, and when
| Item | Detail |
|---|---|
| Railroad | Norfolk & Western. Letter classes. This one is Z |
| Whyte | 2-6-6-2 compound Mallet. High-pressure engine under the cab. Low-pressure engine in front, hinged to the boiler |
| Quantity | 190 locomotives, 1300–1489 |
| Subclasses as built | Z-1, 1300–1314, fifteen, Richmond, 1912, Walschaerts. Z-1a, 1315–1489, 175, Richmond, Baldwin, and Schenectady, 1912–1918, Baker |
| Cylinders | High pressure 22 × 32 in. Low pressure 35 × 32 in. Low-pressure valves were D-slide valves as built |
| Boiler | Delivered at 200 psi. Soon raised to 225 psi. Superheated from the start |
| Drivers | 56½ in on the railroad’s class figures. The 1929 diagram prints 57 in for the Alco engines and 56 in for the Baldwins |
| Tractive effort | 75,830 lb compound. 90,996 lb simple. Both figures are the railroad’s rating at 225 psi |
| Weight, as diagrammed in 1929 | Alco engine 427,000 lb, with 354,500 on the drivers. Baldwin engine 408,000 lb, with 339,000 on the drivers |
| Grate | 72.2 sq ft |
| Z-1b | 74 engines rebuilt in the late 1920s and early 1930s. Piston valves on the low-pressure cylinders, and a Worthington BL feedwater heater. Engine weight 440,000 lb |
| Z-2 | 1399 only. Rebuilt simple at Roanoke in 1928. Rated 93,342 lb. Retired about 1934 |
| Retired | The fifteen Z-1s in 1934. The last of the class in April 1958. All scrapped |
Card dimensions are the Norfolk & Western diagram of December 1929 and the diagram book of March 1955, as compiled by Steve Llanso on Locobase from Allen Stanley’s Rail Data Exchange copies. The 75,830- and 90,996-pound ratings, the 56½-inch class figure, and the Z-2’s 93,342 pounds are the all-time roster compiled with the help of the Norfolk & Western Historical Society, and they agree with the railroad’s own magazine figures for the Z-1a. Service counts for 1942 and 1944 are Ron Rosenberg. Information compiled October 5, 2026.
The first articulateds on the property were a pair of five-engine trials in 1910. Class X-1 was five 0-8-8-0s, numbers 990–994, built by Alco at Schenectady with Walschaerts gear. With no leading truck and no trailing truck they were a poor fit for road service. The railroad superheated them, raised the boiler to 230 pounds, and finished them as hump switchers. They were retired in 1934.
Class Y-1 was five Baldwin 2-8-8-2s, numbers 995–999, the same year. They worked out of Bluefield and between Roanoke and Crewe. The boiler was a separable design, and the engines were the first of the early articulateds to go. The Class Y page dates that retirement to 1924. The 2-8-8-2 returned in 1918 as a different machine, and Roanoke was still building Ys in 1952. That later fleet is a separate story from the five engines of 1910.
The 2-6-6-2 the railroad then bought was the Chesapeake & Ohio’s machine. Richmond had built the C&O’s H-2s in 1911, twenty-four compound 2-6-6-2s with cylinders of 22 and 35 by 32 inches, a grate of 72.2 square feet, and an engine wheelbase of 48 feet 10 inches. Those three figures are the Z’s figures. A 2022 Classic Trains account of the USRA 2-6-6-2 says the Norfolk & Western borrowed one of the 1911 C&O engines and ran it against a Y-1, and that a man who knew the tests reportedly said the C&O engine ran circles around the Y-1. The first Norfolk & Western copies were ordered from the same Richmond works and went into service in April and May 1912.
The fifteen Z-1s, 1300–1314, are Richmond works numbers 51011–51025, built March through May 1912. They are the only engines in the class with Walschaerts gear. From September 1912 Richmond added the Z-1a, the same wheel arrangement with Baker-Pilliod valve gear. Twenty-five engines, works 51469–51493, came in September, October, and November 1912. Forty more, works 53591–53630, came in May 1913. Those eighty Richmond engines are 1300–1379.
Baldwin built the next forty at Eddystone in the summer of 1914. Works numbers run 41483–41486 and 41508–41511 in June, the July blocks 41520–41529, 41531–41536, 41545–41549, and 41556–41558, and 41569–41576 in August. Their road numbers are 1380–1419. The Baldwin boiler was the smaller one. The specification left out nineteen flues at the bottom of the barrel and braced the space they would have occupied, so the Baldwin engines have 224 tubes against the Alco’s 243. The first twenty-five Baldwins were delivered with Street stokers. The last fifteen were delivered with Hanna stokers, which the railway supplied.
Schenectady closed the class. Thirty engines, works 55575–55604, December 1915 through February 1916, are the 1420–1449 group, and 1444 is one of them. Twenty more, works 56456–56475, December 1916 and January 1917, are 1450–1469. The last twenty, works 59869–59888, July 1918, are 1470–1489. Alco’s two works together built 150. Baldwin built 40. The class is 190.
By 1918 the same principal dimensions had gone into the United States Railroad Administration light 2-6-6-2. That engine has 57-inch drivers, a 225-pound boiler, and cylinders of 23 by 32 and 35 by 32. The high-pressure cylinder is an inch larger than the Z’s. Thirty were built, for the Chesapeake & Ohio, as class H-5, and for the Wheeling & Lake Erie. The Norfolk & Western’s own 2-6-6-2s remained the 190 engines in the table below. The C&O fleet, H-1 through the last Baldwin H-6s of 1949, is the Chesapeake & Ohio 2-6-6-2 page.
The figures below are the railroad’s diagram of December 1929, Alco and Baldwin in separate columns, and the later state in the diagram book of March 1955. Both 1912–14 batches left the builders at 200 pounds. The setting was soon raised to 225, and 225 is the pressure under the tractive-effort rating. The class was superheated from the start. The firebox area includes a long combustion chamber, 134 square feet on the Alco engines, and the arch tubes.
Driver diameter is the line on which the documents disagree, and both numbers belong on the page. The 1929 diagram prints 57 inches for the Alco engines and 56 inches for the Baldwins. The Norfolk & Western Magazine reprint, and the all-time roster, use 56½ inches for the class and pair that diameter with 75,830 pounds compound. A computation that uses the diagram’s 57 inches comes out at 74,498 pounds. The rating used here is the railroad’s 75,830, and the simple rating that sits beside it is 90,996.
| Specification | Alco, December 1929 | Baldwin, December 1929 | Later diagram, March 1955 |
|---|---|---|---|
| Class as built | Z-1 and Z-1a, Richmond and Schenectady | Z-1a, Eddystone | Z-1a, as still diagrammed |
| Road numbers | 1300–1379 and 1420–1489 | 1380–1419 | Engines still in the 1955 book |
| Whyte | 2-6-6-2 compound | 2-6-6-2 compound | 2-6-6-2 compound |
| Drivers | 57 in | 56 in | 57 in |
| Cylinders | 22 × 32 in and 35 × 32 in | 22 × 32 in and 35 × 32 in | 22 × 32 in and 35 × 32 in |
| Valve gear | Walschaerts on 1300–1314. Baker on the Z-1a | Baker | Baker |
| Boiler pressure | 225 psi, after delivery at 200 | Delivered at 200 psi, then raised with the class to 225 | 225 psi |
| Driver wheelbase | 20 ft | 20 ft | 20 ft |
| Engine wheelbase | 48.83 ft | 48.83 ft | 48.83 ft |
| Engine and tender wheelbase | 79.21 ft | 79.21 ft | 87.46 ft |
| Weight on drivers | 354,500 lb | 339,000 lb | See the Z-1b weight below |
| Engine weight | 427,000 lb | 408,000 lb | Z-1b rebuilds, 440,000 lb |
| Maximum axle load | 62,600 lb | — | — |
| Tubes | 243, at 2¼ in | 224, at 2¼ in | 213, at 2¼ in |
| Flues | 36, at 5½ in | 36, at 5½ in | 36, at 5½ in |
| Tube length | 24 ft | 24 ft | 24 ft |
| Firebox | 369 sq ft, including 134 in the combustion chamber and 22 in arch tubes | 374.8 sq ft, including 134 in the combustion chamber and 28.8 in arch tubes | 391 sq ft |
| Grate | 72.2 sq ft | 72.2 sq ft | 72.2 sq ft |
| Evaporative heating surface | 5,048 sq ft | 4,742 sq ft | 4,629 sq ft |
| Superheater | 971 sq ft | 1,022 sq ft | 971 sq ft |
| Combined heating surface | 6,019 sq ft | 5,764 sq ft | 5,600 sq ft |
| Tractive effort, compound | 75,830 lb at 225 psi, the railroad’s rating for Z-1 and Z-1a | ||
| Tractive effort, simple | 90,996 lb, the railroad’s simple rating for the same engines | ||
Alco evaporative surface and superheater add to 6,019. Baldwin’s 4,742 and 1,022 add to 5,764. The later 4,629 and 971 add to 5,600. The engine wheelbase, 48.83 feet, is the 48 feet 10 inches of the Chesapeake & Ohio H-2.
The diagrams record three tenders behind the compounds, and a fourth behind the simple rebuild.
| Tender | Water | Coal | Loaded weight | Engine and tender wheelbase |
|---|---|---|---|---|
| As built, 1929 diagram | 9,000 gallons | 14 tons | 167,500 lb | 79.21 ft |
| Later tender on the Alco record | 12,000 gallons | 20 tons | — | — |
| March 1955 diagram | 20,000 gallons | 16 tons | 212,000 lb | 87.46 ft |
| Z-2 1399 | 16,000 gallons | 23 tons | 286,530 lb | 94.56 ft |
The as-built Alco engine at 427,000 pounds plus the 167,500-pound tender is 594,500. The Baldwin engine at 408,000 plus the same tender is 575,500. The 1955 tender behind a 427,000-pound engine is 639,000 for engine and tender. The coal figures, 14 tons, then 20, then 16, are three different tenders on the drawings.
Railway Age Gazette for May 9, 1913, described what the first of these engines were bought to do. The point was to raise the maximum train load. Pusher service stayed. On the Pocahontas Division, between Eckman, West Virginia, and Bluefield, the railroad was using its five 0-8-8-0s, its five 2-8-8-2s, and fifteen of the new 2-6-6-2s, in both road and pusher service.
On the Radford Division, Bluefield to Roanoke, 105 miles, five of the new engines were in road service. The profile included forty miles of 0.4 percent and ten miles of 1.0 percent. On that ten-mile grade the 2-6-6-2 helpers raised the train from 2,800 tons to 4,000. The Gazette’s summary for the division is a 79 percent increase in train load.
Twenty more were road engines between Roanoke and Crewe, 130 miles, and the Gazette says the terminals and the road on that division let them do their best work. A 5,000-ton train left Roanoke with one of the Mallets double-headed by a 4-8-0. Those two engines took the train nine miles to Bonsack, over broken grades. At Bonsack a second Mallet coupled on behind and pushed six miles to Blue Ridge, the ruling grade there 1.2 percent. The pusher cut off at Blue Ridge and returned light to Bonsack. From Blue Ridge the two leading engines hauled 56 miles to Phoebe, broken grades with eight miles of 0.5 percent in them. At Phoebe the 4-8-0 came off, waited for a westbound empty, and double-headed back toward Roanoke. The one Mallet went on to Crewe, 59 miles, broken grade except the 16 miles from Farmville to Burkeville, a continuous 0.45 percent where a 4-8-0 pushed.
On that accounting the Roanoke Division’s train loads were up 43 percent. The forty Mallets in the article, fifteen plus five plus twenty, had taken the place of fifty-seven locomotives, and the number of freight trains on the divisions was down by a quarter. The article is about those forty engines in the spring of 1913. Richmond was then delivering the May 1913 batch, and Baldwin’s forty and all seventy Schenectady engines were still ahead.
The Z-1a’s low-pressure cylinders were built with slide valves. In the late 1920s and early 1930s Roanoke rebuilt 74 of the Z-1as into class Z-1b, seventeen of them Baldwin engines and fifty-seven Alco. The new low-pressure valves were 14-inch piston valves, inside admission, and the engines received a Worthington BL feedwater heater. The all-time roster puts the air pumps on the right side and the engine weight at 440,000 pounds. The fifteen original Z-1s, still on Walschaerts gear, were not in that program. They were retired in 1934.
Ed King’s warning about the class letter is worth keeping next to the count. A Z-1b shows two changes at once. The valve gear was altered on both engines, so the combination lever hangs from the valve stem, and the Worthington heater is on the boiler. Three Z-1as, 1322, 1396, and 1438, were given outside-admission piston valves on the low-pressure cylinders as a trial, the valve travel left as it had been on the slide valves, and the gear left alone. None of the three received a feedwater heater at that time. King reads the trial as a follow-on to Y-2 1700, which had been built with outside-admission piston valves. Number 1438, a Schenectady engine of January 1916, was later finished as a real Z-1b. A photograph at Portsmouth shows it in that form shortly before retirement. Numbers 1322 and 1396 were never converted. King notes that 1322 went to the Interstate Railroad and 1396 to the Tennessee Central still carrying the trial cylinders.
The 74 is Locobase’s count of engines that received both the piston valves and the heater. Many Z-1as ran out their lives with the slide valves they were built with.
In 1928 Roanoke took Z-1a 1399, a Baldwin engine of 1914 from the 1380–1419 group, and rebuilt it as a simple articulated. All four cylinders were high pressure, 22 by 32 inches. The class letter was Z-2. Valve gear stayed Baker. The rebuild carried a double stack. On the 1955 diagram the drivers are 56½ inches, the boiler is at 225 pounds, the engine weighs 441,000 pounds with 377,825 on the drivers, and the tender holds 16,000 gallons and 23 tons at 286,530 pounds. Engine and tender together are 727,530 pounds, on a wheelbase of 94.56 feet. The boiler figures match the later compound diagram: 213 tubes, 391 square feet of firebox, 4,629 evaporative, 971 of superheater, 5,600 combined.
The all-time roster rates that engine at 93,342 pounds. E. W. King, in George H. Drury’s Guide to North American Steam Locomotives, gives the reason it stayed one engine. The boiler was too small to supply four high-pressure cylinders, and the engine was too light for the adhesion the simple arrangement asked of it. It was retired six years after the rebuild, which places the date at 1934, the same year as the original Z-1s.
The simple articulated Roanoke did build, beginning in 1936, was a new design on a new wheel arrangement. Class A is forty-three 2-6-6-4s, numbers 1200–1242, built in the railroad’s own shops through 1950. One survives, No. 1218, at the Virginia Museum of Transportation in Roanoke. The class is the Class A page.
| Class as built | Numbers | Qty | Builder | Works numbers | Built | Notes |
|---|---|---|---|---|---|---|
| Z-1 | 1300–1314 | 15 | Alco, Richmond | 51011–51025 | March–May 1912 | Walschaerts. In service April–May 1912. Retired 1934. None rebuilt to Z-1b |
| Z-1a | 1315–1339 | 25 | Alco, Richmond | 51469–51493 | September–November 1912 | Baker. First Z-1as |
| Z-1a | 1340–1379 | 40 | Alco, Richmond | 53591–53630 | May 1913 | Baker. Completes the Richmond 80, numbers 1300–1379 |
| Z-1a | 1380–1419 | 40 | Baldwin, Eddystone | 41483–41486, 41508–41511, 41520–41529, 41531–41536, 41545–41549, 41556–41558, 41569–41576 | June–August 1914 | Smaller boiler, 224 tubes. Street stokers on the first 25, Hanna on the last 15. 1399 rebuilt to Z-2 in 1928 |
| Z-1a | 1420–1449 | 30 | Alco, Schenectady | 55575–55604 | December 1915–February 1916 | Includes 1444. Number 1438 is the January 1916 engine later finished as a Z-1b |
| Z-1a | 1450–1469 | 20 | Alco, Schenectady | 56456–56475 | December 1916–January 1917 | 1453 and 1457 sold to the Denver & Rio Grande Western |
| Z-1a | 1470–1489 | 20 | Alco, Schenectady | 59869–59888 | July 1918 | Last engines of the class |
The seven rows are the 190 locomotives. Richmond built 80, Baldwin 40, and Schenectady 70. Of the 175 Z-1as, one became the Z-2 and 74 became Z-1bs. The rest of the class stayed compound Z-1as, slide valves and all, until sale or scrap.
| No. | Built as | What happened |
|---|---|---|
| 1300–1314 | Z-1, Richmond, 1912 | Retired in 1934. The Walschaerts engines were not rebuilt |
| 1322 | Z-1a, Richmond | Trial outside-admission piston valves on the low-pressure cylinders. Never a Z-1b. Sold to the Interstate Railroad |
| 1396 | Z-1a, Baldwin, 1914 | The same trial cylinders. Never a Z-1b. Sold to the Tennessee Central |
| 1399 | Z-1a, Baldwin, 1914 | Rebuilt at Roanoke in 1928 as simple class Z-2. Retired about 1934. One engine |
| 1438 | Z-1a, Schenectady, January 1916 | Third engine with the trial low-pressure piston valves. Later completed as a Z-1b |
| 1444 | Z-1a, Schenectady, 1915–16 group | Carried as a Z-1b on the roster at the end of 1942. The engine in the photograph |
| 1453 | Z-1a, Schenectady, 1916 | Sold in 1942. Became Denver & Rio Grande Western 3350, class L-76. Scrapped July 1952 |
| 1457 | Z-1a, Schenectady, 1916 | Sold in 1942. Became Denver & Rio Grande Western 3351, class L-76. Scrapped May 1950 |
The two Rio Grande engines worked mine runs out of Helper, Utah. They were on the Rio Grande’s books by 1943. No other Z is identified here by a second owner. King’s notes on 1322 and 1396 do not give the year of sale.
Rosenberg’s count, in Norfolk & Western Steam (The Last 25 Years), puts the 2-6-6-2 line at 116 engines in 1942 and 116 again in 1944. His all-time maximum for the same line is 190. The original fifteen and the Z-2 were already gone by then. The 116 is what remained of the Z-1as and Z-1bs. His table keeps both letters on one line.
Heavier power had taken the heaviest coal drags. The Ys, and from 1936 the Class A, were the main-line articulateds. The Zs that stayed worked secondary coal trains and yard jobs. Before the S-class 0-8-0s, the railroad’s heavy switching was still in the hands of 4-8-0s, 2-8-0s, and these 2-6-6-2s. Number 1321, a Z-1a, was photographed at Joyce Avenue Yard in Columbus in September 1952.
The diagram record’s last retirement for the class is April 1958. Every engine was scrapped. Nothing of the 190 survives. What the railroad kept in articulated steam is a Class A, 1218, and, from the 2-8-8-2s, Y-3a 2050 and Y-6a 2156. The passenger engine that outlasted the steam program in preservation is Class J 611.
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