NZR DG class
| New Zealand DG and DH class | |
|---|---|
 |
|
| Two DG class locomotives at Dunedin in the early 1980s. | |
| Power type | Diesel-Electric |
| Builder | English Electric and Vulcan Foundry / Robert Stephenson & Hawthorn, United Kingdom |
| UIC classification | A1A - A1A |
| Length | 14.7 metres (48 ft) |
| Weight on drivers | 46.6 tonnes (45.9 long tons; 51.4 short tons) DG 48.4 tonnes (47.6 long tons; 53.4 short tons) DH |
| Locomotive weight | 70 tonnes (69 long tons; 77 short tons) |
| Prime mover | English Electric 6SRKT Mk 2 |
| Engine RPM range | 850 rpm |
| Traction motors | Four EE 525 / 2A |
| Cylinders | I6 |
| Cylinder size | 254 mm × 305 mm (10.0 in × 12.0 in) |
| Top speed | 97 km/h (60 mph) |
| Power output | 560 kW (750 hp) |
| Tractive effort | 114 kN (26,000 lbf) DG 130 kN (29,000 lbf) DH |
| Number in class | 31 DG 11 DH |
| Number | 750 - 791 (original) 2007 - 2497 (TMS) |
| Locale | All of New Zealand |
| First run | 1955—1956 |
| Last run | 1983 |
| Disposition | 0 in service; 4 preserved |
The New Zealand DG and DH class locomotive were a type of diesel-electric locomotives in operation on New Zealand's rail network from 1955—1983, built by English Electric.
Contents |
[edit] Introduction
Due a change in government dieselisation strategy 21 of the original order for DF class were changed to 42 DG class locomotives, being a 'half' version of the DF with only one cab instead of two, and a similar Bulldog nose. The English Electric Co, as they did with many of their diesel locomotives of the 1950s-60s, did not assemble them at the Preston works, but allocated the final assembly of build numbers 2254/E7821-2273/E7840 (road no. 750-769) to Robert Stephenson & Hawthorn and build numbers 2274/D353-2295/D374 (road no. 770-791) to Vulcan Foundry both English Electric plants. The South Island allocated locomotives were initially classified 'DH' because of their higher maximum axle weight and tractive effort. However, DG locomotives from the North Island began operating in the South with the introduction of the Aramoana rail ferry in 1962. As a result, the DH class locomotives were converted to DG class standards in 1968 and received the DG classification, allowing the DH classification to be re-used in 1978.
With the introduction of the DJ class in 1968 the class was usually relegated to "slave" status. The introduction of the new DF class further displaced the class.
[edit] Rebuilds
In an attempt to modernise the locomotives and extend their working lives, ten members of the DG class were rebuilt by Hillside Workshops between 1978 and 1980. The main cosmetic change was to the locomotives' cabs, which were replaced with a New Zealand Railways designed structure. Engineering changes included relocation of the front traction motor blower to a position above the main generator, removal of the A7EL brake controls in favour of a hybrid New Zealand designed push button system, upgrading of traction motors and overseas welding to address cracks in engine blocks. Minor cosmetic changes included addition of steps at the rear of the locomotive for roof access, provision of external door handles and step ladders for mid-loco engine room doors and an automated handbrake system. Six of the recabbed locomotives were members of the Robert Stephenson & Hawthorn built batch. At the same time, nine of the Vulcan Foundry built batch and one of the Robert Stephenson & Hawthorn batch were overhauled to work as slaves (B units) with the recabbed locomotives; they did not receive new cabs and thus were not driven in regular service.
However, the class continued to be plagued by operational problems[citation needed] and were all withdrawn from service at the end of 1983, the slave units being written off first, followed by the recabs. Recab DG 2007 and original 2468 ran a farewell excursion on the Christchurch - Arthurs Pass section of the Midland line on 28 August 1983. This marked the end of the old cab DG service. DG 2007 suffered major failure (con rod through engine block) during the following month. DG 2468 moved to the Weka Pass Railway soon after.
[edit] Preservation
Four locomotives have been preserved: DGs 770 and 791 at the Weka Pass Railway, DG 772 by the Diesel Traction Group at Ferrymead, and a fourth, DG 783, is owned privately and stored at Ferrymead.
Dg 772 is registered and certified for use on the National Rail Network.
[edit] Class register
| Key: | In service | Out of service | Auckland Transport service | Preserved | Overhaul | Scrapped |
|---|
| Original No. | TMS No. | Introduced | Withdrawn | Status | Notes |
|---|---|---|---|---|---|
| DG 750 | 2007 | September 1955 | February 1984 | Scrapped | Recabbed 1979. |
| DG 751 | 2474 | October 1955 | November 1980 | Scrapped | |
| DG 752 | 2036 | October 1955 | February 1984 | Scrapped | Recabbed 1979. |
| DG 753 | 2042 | December 1955 | February 1981 | Scrapped | |
| DG 754 | 2059 | December 1955 | November 1982 | Scrapped | |
| DG 755 | 2065 | December 1955 | April 1980 | Scrapped | |
| DG 756 | 2071 | February 1956 | November 1981 | Scrapped | |
| DG 757 | 2088 | February 1956 | Scrapped | ||
| DG 758 | 2094 | January 1956 | Scrapped | ||
| DG 759 | 2105 | March 1956 | Scrapped | Recabbed 1980. | |
| DG 760 | 2111 | October 1956 | Scrapped | Recabbed 1978. | |
| DG 761 | 2128 | March 1956 | Scrapped | Recabbed 1980. | |
| DG 762 | 2134 | March 1956 | Scrapped | ||
| DG 763 | 2140 | April 1956 | Scrapped | Recabbed 1979. | |
| DG 764 | 2157 | April 1956 | Scrapped | ||
| DG 765 | 2163 | May 1956 | Scrapped | ||
| DH 766 | 2186 | August 1956 | Scrapped | ||
| DG 767 | 2192 | July 1956 | Scrapped | ||
| DG 768 | 2480 | July 1956 | Scrapped | ||
| DG 769 | 2226 | September 1956 | Scrapped | ||
| DG 770 | 2232 | June 1956 | Preserved | Weka Pass Railway, Waipara. | |
| DG 771 | 2249 | May 1956 | Scrapped | ||
| DG 772 | 2255 | August 1956 | Preserved | Ferrymead Railway, Christchurch. | |
| DG 773 | 2261 | June 1956 | Scrapped | ||
| DG 774 | 2278 | September 1956 | Scrapped | ||
| DG 775 | 2284 | August 1956 | Scrapped | ||
| DG 776 | 2290 | September 1956 | Scrapped | Recabbed 1980. | |
| DH 777 | 2301 | August 1956 | Scrapped | ||
| DH 778 | 2318 | August 1956 | Scrapped | ||
| DH 779 | 2324 | September 1956 | Scrapped | ||
| DH 780 | 2330 | September 1956 | Scrapped | Recabbed 1980. | |
| DH 781 | 2347 | September 1956 | Scrapped | Recabbed 1979. | |
| DH 782 | 2497 | September 1956 | Scrapped | ||
| DH 783 | 2376 | October 1956 | Preserved | Stored at Ferrymead Railway. | |
| DG 784 | 2382 | September 1956 | Scrapped | ||
| DG 785 | 2399 | September 1956 | Scrapped | ||
| DG 786 | 2416 | October 1956 | Scrapped | ||
| DG 787 | 2422 | November 1956 | Scrapped | ||
| DG 788 | 2439 | November 1956 | Scrapped | Recabbed 1980. | |
| DG 789 | 2445 | December 1956 | Scrapped | ||
| DG 790 | 2451 | December 1956 | Scrapped | ||
| DG 791 | 2468 | December 1956 | Preserved | Weka Pass Railway, Waipara. |
[edit] References
- "NZR Locomotives and Railcars 1983". T A McGavin. New Zealand Railway and Locomotive Society : Wellington, New Zealand : 1983.
- "New Zealand Railway Diesels". E J McClare. Southern Press : Wellington, New Zealand.
- "The Life and Times of the NZR's DG Class Diesel-Electric Locomotives". P J R Dunford, New Zealand Railway Observer No.230. New Zealand Railway and Locomotive Society : Wellington, New Zealand : 1997.
[edit] External links
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