History
Class U2 was numerically the largest class of locomotives on the NCC, only being equalled when the last of the Class WT 2-6-4 tank engines was delivered in 1950. The first of the class was built in 1924 and construction continued over the following thirteen years until the last engine was outshopped in 1937.
The Class U2 engines can be divided into four sub classes as follows:
The renewals were an accounting device to avoid the capital charges associated with building new engines; it is unlikely that much of the original engines was incorporated into the resulting U2s.
The engines were simples, i.e. not compound, with two 19 in × 24 in (483 mm × 610 mm) inside cylinders. Their boilers were rated at 170 pounds per square inch (1.17 MPa) and were fitted with Schmidt superheaters. All eighteen engines, though differing slightly in appearance had, until 1945, the same power output. The only dimensional difference was caused by six boilers, identical with the others, except that the opportunity had been taken for the first time with a Derby boiler to use the broader Irish gauge to full advantage for a wider firebox. The first two of these G7S boilers were fitted to Class A "Heavy Compounds" Nos.67 and 59 when they were renewed as Class U2 in 1934.
Two years later, four more of this type of boiler were ordered when No.87 was constructed out of Class A No.63 and Nos.72 and 73 were rebuilt from Class U to U2. The remaining boiler was presumably to have a been a spare one to enable speed shopping of engines but in the event it was immediately fitted to No.78. This engine was the last of the NBL engines to be built in 1924 but she had run a considerably greater mileage (442,681 miles or 712,430 kilometres) than other members of the class by the time she received the new boiler in October 1936.
No.70 did not have its footplate altered when it was rebuilt from Class U to U2; the short footplate made it unpopular with locomotive crews as the cab became very warm in summer and the position of some of the controls, especially the reversing lever, was cramped. It had the same nominal weight, 51 long tons 10 cwt (115,400 lb or 52.3 t), as the rest of the class,
The new locomotives were supplied with Fowler-type flush-sided tenders with a capacity of 5 tons of coal and 2,500 imperial gallons (11,000 L; 3,000 US gal) of water. The rebuilt locomotives were coupled to the original BNCR-type six-wheeled tenders which could carry 6 tons of coal and 2,690 imperial gallons (12,200 L; 3,230 US gal) of water.
Apart from a slight difference in the cab, the superb external finish of the NBL engines appears to have given them an advantage in prestige among the crews over the three Belfast-built engines. Although less than half of the class had been built in Glasgow, the U2s gained the general nickname of "Scotch Engines".
Eleven of the engines were named after Ulster castles and a twelfth, No.87, carried the name Queen Alexandra.
The U2s provided the top-link workings on the NCC until the arrival of the Class W Moguls in 1933. The fastest timing for the Portrush expresses that the U2s worked in 1932 was 82 minutes for the 58.3 miles (93.8 km) from Greenisland to Portrush, over half of the route being over a single line. They also worked the Larne Harbour boat trains, being allowed 30 minutes for the 24⅓ miles, again over a route with a significant proportion of single track.
While most of the class were based at Belfast, Nos.70, 73 and 80 were at one time assigned to Larne shed and Nos.74 and 81 were at Coleraine. In later years, No.77 was also based at Coleraine and would be one of the last engines to work a train over the Derry Central line before it closed.
The U2s performed sterling service during the busiest years of World War II. A typical job was to take over a military train at Antrim that had been worked through from the GNR(I). Having hauled eight bogie coaches from Antrim to the summit of the NCC main line, a stop would be made at Ballyclare Junction to attach carriages that had arrived from Derry or Cookstown on a previous train before travelling on to Larne Harbour where it was common to see trains of twelve or more bogie coaches arriving.
In 1945–1946, Nos.71 and 81 had the diameters of their cylinders reduced from 19–18 in (483–457 mm). It is possible that the cylinders fitted to No.72 came from Class U1 engine No.3 which had just been withdrawn. Originally fitted with Fowler pattern chimneys that had capuchons, some the class, such as No.76, later received a Stanier type and it was said by their crews that they never steamed as well after this alteration.
The Ulster Transport Authority (UTA) arranged a massive sale of withdrawn locomotives in January 1956 which included the first U2s to be withdrawn. These were Nos.70, 79, 82 and 83 at Carrickfergus and Nos.71 and 77 brought up from Ballymena. The remainder of the class were withdrawn over the following seven years. The last to go in June 1962 was No.74 Dunluce Castle which was destined for preservation.
Building and withdrawal data
The following table summarises the building and rebuilding history of the Class U2 locomotives:
U2
No. | Builder | Date built | Name | Orig.
Class | Orig.
No. | Re-No./
Date | Rebuilt as U2 | Date rebuilt | Withdrawn | Notes |
|---|
| 70 | MR, Derby | Jul 1914 | | U | 70 | | NCC, York Rd | Nov 1924 | Jan 1956 |
| 71 | MR, Derby | Jul 1914 | Glenarm Castle | U | 69 | 71 / 1923 | NCC, York Rd | Mar 1927 | Jan 1956 |
| 72 | MR, Derby | Dec 1922 | | U | 14 | 72 / 1923 | NCC, York Rd | Feb 1937 | Dec 1961 |
| 73 | MR, Derby | Dec 1922 | | U | 15 | 73 / 1923 | NCC, York Rd | Dec 1937 | Jun 1956 |
| 74 | NBL, Glasgow | Jul 1924 | Dunluce Castle | | | | | | Jun 1962† | Preserved |
| 75 | NBL, Glasgow | Jul 1924 | Antrim Castle | | | | | | Jun 1956 |
| 76 | NBL, Glasgow | Jul 1924 | Olderfleet Castle | | | | | | Sep 1959 |
| 77 | NBL, Glasgow | Jul 1924 | | | | | | | Jan 1956 |
| 78 | NBL, Glasgow | Jul 1924 | Chichester Castle | | | | | | Mar 1960 |
| 79 | NCC, York Rd | Aug 1925 | Kenbaan Castle | | | | | | Jan 1956 |
| 80 | NCC, York Rd | Nov 1925 | Dunseverick Castle | | | | | | Dec 1961 |
| 81 | NCC, York Rd | Dec 1925 | Carrickfergus Castle | | | | | | Aug 1957 |
| 82 | NBL, Glasgow | May 1925 | Dunananie Castle | | | | | | Jan 1956 |
| 83 | NBL, Glasgow | May 1925 | Carra Castle | | | | | | Jan 1956 |
| 84 | NCC, York Rd | May 1905 | Lissanoure Castle | A | 20 | as renewed | NCC, York Rd | Dec 1929 | Dec 1961 |
| 85 | MR, Derby | Jun 1908 | | A | 67 | as renewed | NCC, York Rd | May 1934 | Mar 1960 |
| 86 | NCC, York Rd | Aug 1906 | | A | 59 | as renewed | NCC, York Rd | Sep 1934 | Mar 1960 |
| 87 | MR, Derby | May 1905 | Queen Alexandra* | A | 63 | as renewed | NCC, York Rd | May 1936 | Aug 1957 |
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- The name Queen Alexandra was transferred from Class A No.34 to No.63 in November 1932.
- † Preserved.
An Irish 2P?
The NCC's Class U2 locomotives showed a strong Midland Railway influence in their design and bore a superficial resemblance to the LMS Class 2P 4-4-0 locomotives. However, one should not regard the U2s as an Irish equivalent of the LMS 2P; they were quite different engines. That the two classes had little in common is shown by a comparison of principal dimensions:
| NCC U2 | LMS 2P |
| Driver size: | 6 ft 0 in (1.83 m) | 6 ft 9 in (2.06 m) | |
| Locomotive weight: | 51 ton 10 cwt | 54 ton 1 cwt |
| Boiler pressure: | 170 psi (1.17 MPa) | 180 psi (1.24 MPa) |
| Cylinders: | 19 in × 24 in (483 mm × 610 mm) | 19 in × 26 in (483 mm × 660 mm) |
| Valve gear: | Walschaerts | Stephenson link |
| Tractive effort: | 17,338 lbf (77.1 kN) | 17,730 lbf (78.9 kN) |
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