4-4-2 Steam Locomotives in Great Britain

Class 4CC (Locobase 2275)

Most data from "Four-Cylinder Compound Locomotives, North Eastern Ry.," The Locomotive Magazine, Vol XII (15 May 1906), p. 73; "Balanced 'Atlantic' Compound Engines: North Eastern Railway", Railway Engineer, Volume 27, Number 7 (July 1906), pp. 220-221. See also Richard Marsden, "The Worsdell C8 (NER Class 4CC) 4-4-2 Atlantics" in his online LNER Encyclopedia at [], last accessed 23 October 2014; O S Nock, Locomotives of the North Eastern (1954); and See also Malcolm Peirson, "Compounds" in Marsden's LNER Encyclopedia at [], last accessed 17 April 2025. (Thanks to Alex Blessing for his 4 April 2025 emial supplying details from the Railway Engineer account he supplied to Locobase. including tube length, engine wheelbase, axle loading, tender weight ).

Walter Mackersie Smith, an assistant to Wilson Worsdell, designed these two four-cylinder balanced compounds rather than the more characteristic three-cylinder variety. (Smith's other compound engines used a three-cylinder system.) In addition to the rarely used compound driver, their use of square-topped Belpaire fireboxesprovided a unique combination of design features on the NER.

All four cylinders drove the lead coupled axle. Each set of outside HP and inside LP cylinders drove cranks that were offset 180 degrees 730 had Stephenson link, 731 Walschaert radial valve gear driving HP valves of 7 1/2" (191 mm) diameter and LP valves measuring 10" (254 mm) across. (731 would be the only NER engine ever to use Walschaert gear.)Peirson reported Wordsell's conclusion that the ideal compounding ratio should be LP 2.3:HP ]; the 4CC design sastisfied that criterion exactly.

Marsden observed that Smith's design was an "immediate success and in December 1907. Nock wrote that dynamometer car tests showed these compounds to be "markedly superior to the Class V engines ...These two engines," Nock asserted, "were in very truth masterpieces of locomotive design: extremely powerful ...and graceful to a high degree from whatever angle they were viewed."

Worsdell authorised the building of ten more with Walschaerts valve gear, and the C8 may have become a standard NER type." Smith's plans for a class of compounds were defeated by his death in October 1906, five months after the pair were introduced and a demand by his executors for royalty payments. The NER Board chose to cancel the ten-engine order instead.

Even so, the NER couldn't ignore the duo's sterling qualities and superheated them along with other Atlantics; see Locobase 3530.

Class 4CC -- superheated / C8 (Locobase 3530)

Data from Richard Marsden, "The Worsdell C8 (NER Class 4CC) 4-4-2 Atlantics" in his online LNER Encyclopedia at [], last accessed 23 October 2014. See also Malcolm Peirson, "Compounds" in Marsden's LNER Encyclopedia at [], last accessed 17 April 2025.

Locobase 2275 describes this pair of Walter Mackersie Smith's four-cylinder balanced compounds as they left the works in 1906. A series of the NER valued the surviving duo, rating them well above most other express designs. Superheating the two surviving 4CCs occurred in 1915. The engines had relatively capacious boilers and the flues and elements seemed to have fit easily, as the review of the heating surface areas would suggest.

Apparently, the NER found the benefits of compounding steam sufficient to allow the reduction of 25 psi (1.7 bar) in the boiler pressure setting.

As many of Great Britain's railways fell into the four major Groups in 1923, the 4CCs landed on the LNER's roster as their bclass C8. A dccade later,731 was withdrawn followed by the 730 in 1935.

Class Class Z1/LNER C7 (Locobase 1495)

Data from E L Ahrons, The British Steam Locomotive from 1825 to 1925 (London: Ian Allan, 1926); and Railway World (12 May 1911), p. 372. See also [] (visited November 2002) -- then the London & North Eastern Railway Locomotives page; Richard Marsden's LNER Encyclopedia [], last accessed 11 January 2016, whose superheater area Locobase adopts in the specifications; and "Recent NER Locomotives Class 'Z1' Superheater Engines, Atlantic Type, Three Cylinders", Locomotive Magazines, Volume XIX [19] (15 January 1913), pp. 13-14. For the "semi-uniflow" 2212, see "Three-Cylinder 'Uniflow' Locomotive, North Eastern Railway", Locomotive Magazine, Volume XXV [25], No 323 (15 July 1919), pp. 101-103. For the trailing-truck booster, see "Articulated Locomotives:Their Evolution and Advantages", Railway Wonders of the Worlds at [], last accessed 5 December 2020.

Designed by Vincent Raven and built at the same time as the Zs, but given Schmidt superheaters and cylinder diameters greater by 1" (25.4 mm). The comparison clearly favored the Z1s and a later batch of 30 built at the North Eastern's Darlington shops also were superheated. LM's 1913 report said that these were the first express engines in England to combine manufacture of all three cylinders and their 7 1/2" (191 mm) piston valves in one casting. (Ahrons gives a slightly lower evaporative heating surface of 1,476 sq ft [137.13 sq m]; this may reflect the difference between the two batches.)

The class was put to work hauling 350-400 ton trains between York and Edinburgh. They averaged 53.8 mph (85.5 kph) over the 80.5 miles (130 km) between York and Newcastle and 50-54 mph (80.5-90 kph) over the 124.5 miles (200.5 kph) from Newcastle to Edinburgh.

In tests, these engines developed 1,090 drawbar horsepower pulling a 545-ton load at 58 mph. OS Nock (1954, Locos of the NER) reported that 1924 trials showed the three-cylinder Z1s to be significantly better than their two-cylinder V1 predecessors. They burned 25% less coal per drawbar horsepower hour and consumed 17% less water. By then, an average Z engine had traveled farther between repairs, and stretched the wear of the outer tire on the drivers much further as well..

The London & North Eastern Railway Locomotives page offered an impressive variety of experiments conducted on members of this class. For one thing, the last in the class (2212) was built with Stumpf Uniflow cylinders. (The 1919 LM article describes the use of piston valves as auxiliaries to address the main problem of using uniflow cylinders in a locomotive.) Another class member received Lentz rotary poppet valve gear.

Others tried out the Dabeg feedwater heater (2163), the ACFI water treatment system (2206 and 728), and two tested a trailing-truck booster. A heading photograph in the Railway Wonders show the setup. Replacing the single-axle trailing truck was a bogie pivoting under the cab that placed the rear axle under the front of the tender. A two-cylinder booster engine turned the rear axle. The other two tender axles also rode in a bogie. RW called it a "temporarily articulated" arrangement and commented that the wheel arrangement couldn't "be described by the standard system." [Maybe 2-4-2+0-2-0?

At least 14 survived to be included in the BR stud in 1948, but these were retired soon after.

Class V (Locobase 2290)

Data from E L Ahrons, The British Steam Locomotive from 1825 to 1925 (London: Ian Allan, 1926); and "New 'Atlantic' Locomotive, NER," The Locomotive Magazine, Vol IX (19 December 1903), p. 349.

A Wilson Worsdell design with larger than usual cylinders, but smaller grate. 10" piston valves were fitted inside the frames.

The data suggest a nicely balanced blend of power and economy. The report from LM noted that this class was "one of the largest and most powerful machines so far designed and built in this country for passenger servicet". Its bulk "...closely approximat[es] the extreme limits possible with the British loading gauge for a locomotive of ordinary outline." A side effect of this encroachment was to limit the driver's forward vision.

Superheated in 1914 using a boiler that was interchangeable with the Class Z locomotives; see Locobase 1495 for specifications. Later classed on the LNER as the C6. The generous boiler dimensions probably help to account for the durability of this class; the last of these weren't retired until 1948.

According to [] (visited November 2002), the C6 designation included 10 V/09s that were built in 1909 to a modified design. The cylinders shrank 1/2" to 19 1/2" diameter and the running plate and splashers were altered, too.

Class Z (Locobase 1494)

Data from "Three Cylinder 4-4-2 Locomotives, North Eastern Railway", The Locomotive Magazine, Volume XVII (15 November 1911), p. 243; "Express Passenger Locomotive for the North Eastern Railway, Atlantic Type," Railway and Locomotive Engineering, Vol XXV, No 2 (February 1912), p. 43; and "Railway Developments in Europe," Railway World (12 May 1911), p. 372.

Vincent Raven built twenty engines in this year, 10 as Z without superheaters, 10 as Z1 with superheaters. The order went to North British of Glasgow because the railway's shops had no openings on the production line.

These Zs had three cylinders and 7 1/2 " (191 mm)diameter piston valve chambers cast in one piece. Max cutoff was 65% and "notch 1" cut steam off at 15% of stroke. LM reports that the Zs were "urgently required to deal with the ever-increasing East Coast passenter traffic between York, Newcastle, and Edinburgh. A later report in American Engineer said that the class had been "very successful in handling trains of from 300 to 500 tons behind the tender at average speeds of 53 miles per hour."

The Zs wer.e superheated in 1914-1915 and all of these Atlantics were then called the Z1 class ( (Locobase 1495)