| GNR(I) class SG | |
|---|---|
| Power type | Steam |
| Designer | Charles Gifford |
| Builder | Beyer, Peacock & Co., Nasmyth, Wilson and Company |
| Build date | 1913, 1915, 1924–1925 |
| Configuration | 0-6-0 |
| UIC classification | 2'Bh |
| Gauge | 5 ft 3 in (1,600 mm) |
| Driver diameter | 5 ft 1 in (1.549 m) |
| Superheater type | Schmidt |
| Valve type | 8-inch (200 mm) piston valves |
The Great Northern Railway (Ireland) SG and SG2 classes was one of the last designs of Charles Clifford. These locomotives were the first GNR(I) designs to be fitted with Schmidt superheaters and 8-inch (203 mm) piston valves, the SG class having a re-designed motion with rocker arms as well as the first to have 5 ft 1 in (1.549 m) wheels instead of 4 ft 7 in (1.397 m).
More locomotives were added in 1915, but with further alterations from Clifford’s design. Classified 52 and 502, They had direct motion (without rocker arms) driving inclined piston valves, and Robinson superheater. The only external difference in respect of the model was the weighshaft being a little higher on the S02 resulting in the reversing rod being higher, which in turn resulted in the rear of the left hand side sandbox rod being inclined upwards from the centre sandbox back to the firebox. Also the Wakefield mechanical lubricator was mounted further back on the 502. These locomotives were also fitted with Ross pop safety valves as built. The 1913 batch had lever safety valves changed to Ross pop type after first major overhaul after 10 years.
Engines were originally built with flush riveted smokeboxes. After first major overhaul domed rivets were used. A further batch of 502’s were built in 1924/25 by Nasmyth, Wilson and Company, the previous two lots having been built by Beyer, Peacock and Company. The major difference was in the brake rods of which there were two inboard of the wheels. The earlier SO and 562 locomotives had 4 pull-rods the outer ones being outside of the wheels. (Photos suggest that some of these locomotives were converted later to inner pull-rod type.) The other differences for the modeller to note are that the 1924 batch had beading on the splasher sides above the sub-splashers, and of course were fitted with triangular Nasmyth, Wilson builders’ plates on the leading splashers. Beyer, Peacock locomotives of 1913 and 1915 had oval plates on the centre splashers.
Although primarily intended for goods work, the increased wheel diameter was intended to allow use for passenger duties, and they proved most useful for some passenger work and took heavy excursion trains with ease and speed.
When first brought into service, the five SG’s were originally numbered 137, 138, 37, 40 and 41. Very soon, however, the last three were renumbered 47, 48, 49 and the whole series again renumbered 175, 176, 177, 178, 179. These locomotives originally ran with flared tenders, but at a later date 3,500 imperial gallons (16,000 l; 4,200 US gal) straight sided tenders, as supplied in the kit, were also used. All locomotives were fitted with 3 link couplings and tenders with screw couplings.
On the break-up of the GNR(I) in 1958, Córas Iompair Éireann took over a number of these locomotives for a period of five years up to the end of steam on CIÉ. They were used particularly on the ex-DSER services to Wexford and Rosslare. CIÉ retained the GNR(I) numbers, with suffix N except in the case of No.19, also ‘CIE’ was stencilled on the locomotive buffer beams. After withdrawal, some locomotives, including 15N, 179N, and 181N were kept in reserve by CIE, some until 1965.
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