NZR DX class

"DXC" redirects here. For the video game sometimes abbreviated as such, see Castlevania: Rondo of Blood#Castlevania: The Dracula X Chronicles.

New Zealand DX class
DXB 5143, the first locomotive to be painted in the KiwiRail livery, stands at Wellington Railway Station Platform 9 on 1 July 2008.
Power type	Diesel-Electric
Builder	General Electric, United States
Model	U26C
Build date	1972 - 1975
UIC classification	Co-Co
Gauge	1,067 mm (3 ft 6 in) Cape gauge
Length	16.9 metres (55 ft 5 in)
Width	2.74 metres (9 ft 0 in)
Height	3.70 metres (12 ft 2 in)
Axle load	DX 16.25 tonnes (15.99 long tons) DXR 17.5 tonnes (17.2 long tons)
Weight on drivers	DX 97.5 tonnes (96.0 long tons) DXR 105 tonnes (103 long tons)
Locomotive weight	DX 97.5 tonnes (96.0 long tons) DXR 105 tonnes (103 long tons)
Prime mover	General Electric 7FDL-12
Engine RPM range	400 - 1050 rpm
Aspiration	Turbocharged
Alternator	General Electric GTA-11
Traction motors	Six
Cylinders	V12
Transmission	25/64 gear ratio
Top speed	105 km/h (65 mph)
Power output	DX/DXB/DXC 2,050 kW (2,750 hp) original 2,240 kW (3,000 hp) uprated DXB/DXC/DXR 2,420 kW (3,250 hp)
Tractive effort	DX 259 kN (58,000 lbf) continuous
Number in class	49
Number	2600 - 2648 (original) 5016 - 5520 (TMS) DXR 8007, 8022
Nicknames	"Dixies" (DX) "The Pig" (DXR 8007)
First run	DX 1972 DXR 1993 DXC 1997
Disposition	2 rebuilt as DXR (both in service) 1 withdrawn 46 in service

The New Zealand DX class is a class of 49 Co-Co diesel-electric locomotives that currently operates on New Zealand's national railway network.

Built by General Electric in Erie, Pennsylvania, United States, they were introduced to New Zealand between 1972 and 1976. The class is based on the General Electric U26C model, a narrow-gauge version of the GE U23C model. The U26C is also used in South Africa (see South African Class 34-900), Brazil, Kenya, and, in modified form, in Tanzania/Zambia.

The locomotives have seen several upgrades since their introduction and three versions now exist; the DXB, DXC and DXR.

Introduction

DX 2626 (now DXC 5287), in the class's original Clockwork Orange livery, departs Wellington with a tank train in the late 1970s.

DX 2608 (now DXB 5097) hauling the Silver Star overnight passenger train during the 1970s.

The DX class was introduced in response to a requirement for a more powerful locomotive to handle traffic on the North Island Main Trunk. Before their introduction the heaviest freight and passenger trains on the line required two members of the 1,060-kilowatt (1,420 hp) DA class to haul them. The DX class could haul heavier and faster trains than two DA's, even though they produced 70 kilowatts less than the combined DA's, as the single DX weighed 97.5 tonnes compared to the two DA's combined weight of 162 tonnes.

The first 15 members of the class (DX 2600 - DX 2614) were introduced in 1972. Initially, they were confined to the NIMT as their 16.25-tonne axle load was too heavy for many of the bridges on the other lines. As it was several bridges and viaducts on the NIMT had to be strengthened to take the weight of the locomotives.

There is no clear reason why the class was named the DX class. Diesel mainline locomotive clases begin with "D", followed by another letter - the mystery was why "X". Up to the DX class introduction, all classes had used letters A to J, and shunting locomotives used S. One possible explanation for the X was a reference to the 4-8-2 NZR X class steam locomotives, which ran on the central section of the NIMT between 1909 and 1957, and at the time of their introduction were the most powerful steam locomotives on NZR.

With bridges progressively strengthened throughout the North Island, and to further increase capacity on the NIMT in particular, 34 more members of the class were introduced in 1975 and 1976.

In service

History

DX 5310 and DQ 6324 on a freight train cross the Taylor River in Blenheim. Note the DXR-style long hood on 5310.

The DX class was initially used for heavy freight trains on the NIMT, especially on the central section where the power was needed. Most of the 49 class members in service by 1976 were used on this line, but a few also operated between Palmerston North and New Plymouth via the Marton - New Plymouth Line most days of the week, and also occasionally on passenger trains between Wellington and Masterton on the Wairarapa Line. In 1974 a DX ventured along the North Auckland Line as far north as Whangarei, and thereafter they saw occasional use in Northland in the late 1970s and early 1980s, but did not have any regular assignments there.

From introduction in 1972 a member of the class was assigned to haul the prestigious Silver Star overnight NIMT passenger express. Previously, the train required two DA class locomotives. The DX class was also used on the Northerner overnight passenger train when it was introduced in 1975.

In 1988 a major reshuffle of the mainline locomotive fleet took place nationwide as a result of the opening of the NIMT electrification and introduction of the EF class to handle the central section. For the DX class, this meant leaving the upper North Island, and being split into two fleets for service between Wellington and Gisborne/New Plymouth, and in the South Island. This was the first use of the class on the Palmerston North - Gisborne Line and the northern section of the Wairarapa Line between Masterton and Woodville.

In the mid-1990s, a small number of DX's returned to Auckland for use between Auckland and Tauranga via the East Coast Main Trunk, on the Kinleith Branch and regular service between Auckland and Whangarei. This was the first use of the class in regular service east of Hamilton. In 2000, a DX ventured north of Whangarei, which remains the last expansion phase of DX class territory.

Two DXC locomotives on a Greymouth to Lyttleton coal train.

Current

The DX class is still used primarily on heavy freight trains. The majority of the class now operate in the South Island, predominantly hauling coal trains between the West Coast mines and the port of Lyttelton near Christchurch. The trains consist of up to 30 CE class hopper wagons each holding 52 tonnes of coal, and require five members of the class to haul the train up the 3% (1 in 33) west-east grade of the Otira Tunnel, and two members to haul it on the other sections of the line. These services are now exclusively hauled by the DXC sub-class. The class are also involved in general freight operations, and also employed periodically to haul the TranzAlpine and Coastal Pacific passenger trains.

In the North Island the DXB sub-class are the primary haulers of milk trains to Fonterra's Whareroa factory near Hawera on the MNPL, usually operating in pairs to haul these trains up the 1 in 35 Westmere Bank north of Wanganui. The class is also involved in other freight operations in the lower North Island, usually operating singly or in multiple with other locomotives.

A small number, including both DXRs, were based in the upper North Island, primarily in general freight use on the ECMT. With the allocation of the new DL class locomotives to that area, these locomotives were transferred to the South Island in late 2011.

The class are also periodically used to haul through trains on the central NIMT when EF locomotives are unavailable or the electrification requires maintenance. They are the primary haulers of the Capital Connection service between Palmerston North and Wellington and see occasional servicing hauling the Overlander.

Numbering

The DX class was originally numbered from DX 2600 to DX 2648 - which in common with NZR practice of the time was based on power output (2600 hp).

With the introduction of the computerised Traffic Monitoring System (TMS) in 1980, the class was renumbered. The DX class received four-digit numbers starting with 5, in which the fourth number is a check digit for the number. The locomotives were numbered in order, with DX 2600 renumbered DX 5016 (6 being the check digit) and DX 2648 renumbered DX 5517. The numbers 500x, 515x, 534x and 549x were not used as these as these numbers do not generate a valid check digit, and DX 2639 never received a TMS number as it had been withdrawn by then.

The DXB and DXC sub-classes have kept their original TMS numbers, while the DXR sub-class received new TMS numbers beginning with 8, numbered irrespective of their DX number. DX 5045 received a new TMS number using the DXR algorithim (5520) when it was upgraded and returned to service following being involved in a fatal derailment at Te Wera in 2002.

Livery

Upon introduction, all the DX class members were painted in "clockwork orange". The livery consisted of the locomotive body painted orange except for a yellow segment at the top of the locomotives - roughly the same shape and size as the orange segment on the original KiwiRail livery.

Between 1977 and 1986, the entire class was repainted in the "Fruit Salad" livery - red, grey, and yellow, which most of the class wore until the end of the decade. This livery had the road numbers displayed on the sides of the locomotives in large white numbers with DX 2612 the first to be painted as such. Since then, members of the DX class have received liveries including Cato Blue (Fruit Salad with blue instead of red), Bumble Bee (black and yellow), Corn Cob (green and yellow) and the KiwiRail phase 1 and 2 schemes (grey, orange or red, and yellow). No DX's remain in the Fruit Salad or Cato Blue liveries.

Upgrades

The locomotives received an upgrade during 1988 with the introduction of single-manning to improve visibility for the driver, with a large single front window replacing the original two small windows.

Sub-Classes

There are two sub-classes of the DX - DXB and DXC.

The classifications DXB and DXC reflect modifications that have been carried out to the fleet. These include heavier drawgear, uprated engines, new cabs, DC class-style low short hoods (some have received DFT-style low hoods) and higher power traction motors.

The designation DXB denotes that the locomotive has been fitted with the Brightstar electronic traction control system, while DXC denotes that the locomotive has been additionally fitted with modified air intakes (“chutes”) as well as all the other upgrades including Brightstar. Thirteen of the original batch of 15 have been upgraded to DXB standard (DXC 5039 and DX 5045/DXC 5520 being the exceptions), and most of those from the subsequent batches upgraded to DXC standard - exceptions being DX 2639 (long since withdrawn from service), DX 5448 (upgraded to DXB only, due to a cracked frame suffered in a collision in 1999) and those rebuilt to DXR (DXs 5362 and 5235).

Generally the DXC sub-class is assigned to the South Island, as the modified air intakes were designed to assist in are useful for working the Midland Line, coal trains (see above) particularly in the formerly electrified Otira Tunnel section, whereas the DXB sub-class is predominantly assigned to the North Island. However, it is not uncommon for the two sub-classes to stray, with four DXB’s now assigned to the South Island and DXC’s often used in the North Island to prove reliability after repairs before returning south. The DXB’s in the South Island do not work the coal trains.

The plain DX class is designated by GE as U26C, the newer upgrades are designated C26-MMI (2,750 hp DXB/DXC) and C30-MMI (3,250 hp DXB/DXC).

Rebuilds: DXR class

DXR 8007 in New Zealand Rail's corporate colours, 1993

DXR 8022 in Toll Rail colours

DXR 8007 with KiwiRail logo, 2009. Note the remodified cab.

In 1993, New Zealand Rail Limited undertook a significant rebuilding of DX 5362 into the first of what was to be a new sub-class, the DXR. DX 5362 had been stored out-of-service at Hutt Workshops since early in 1989 suffering a cracked frame; it was rebuilt and became the first of the intended new sub-class. The use of 'R' (like the DBR class) denotes that the DX had been rebuilt. The locomotive featured a new diesel engine, new upgraded traction motors and a radically different appearance to other DX class locomotives, with an enlarged "Universal Cab". GE classified the rebuild as C30-7M (DXR).

The DX rebuilding programme was to be much like the rebuilding of the DF class into the DFT class, but after the privatisation of New Zealand Rail Limited (renamed Tranz Rail in 1995) later in 1993, the new management decided not to undertake further DX class rebuilds. One locomotive was however rebuilt to these original DXR specifications during the Tranz Rail years, DX 5310 in 2001 for its return to service following its derailment at Pukehou while hauling the Bay Express in 1995. It did not though receive a new DXR style cab, so retained its original DX classification and now carries the designation DXC 5310 after being overhauled and fitted with chutes in late 2010.

Following the purchase of Tranz Rail by Toll in 2003, the new management authorised the rebuild of DX 5235 - itself having been stored since being damaged in a collision in Christchurch in 2000 - which became DXR 8022. The new DXR did not follow the same lines as the previous locomotive, and in 2006 DXR 8007 was again rebuilt at the Hutt Workshops more closely along the lines of the newer DXR. In 2007, DXR 8022 was one of the locomotives involved in a biofuel trial using of a fuel mix of 5 per cent biodiesel and 95 per cent regular diesel over a period of six months. With the introduction of the DL class locomotives into service the two DXR's have been transferred to the South Island where there are employed in general freight on the major lines.

At 2,420 kilowatts (3,250 hp), the DXR class was the most powerful class of diesel-electric locomotive ever operated in New Zealand, until the introduction of the DL class in 2010, which surpassed the DXR's power output with 2,700 kilowatts (3,600 hp).

Withdrawals

As of 2011, only one DX class locomotive had been withrdawn from service. DX 2639 was involved in a crash south of the Parnell Tunnel near Newmarket station, at around 4:00pm on 23 March 1977. The locomotive was hauling a Wellington to Auckland express freight train when it crashed head-on into an Auckland to Helensville passenger train being hauled by DA 1426 that was on the wrong line. The cause was related to human error during a signalling failure. DX 2639 was subsequently written off and scrapped after less than a year in service.

Class register

Key:	In service	Out of service	Auckland Transport service	Preserved	Overhaul	Scrapped

TMS No.	Original No.	Livery	Introduced	Withdrawn	Status	Allocated to	Notes
DXB 5016	2600	KiwiRail	01972-11 November 1972		In service	North Island
DXB 5022	2601	KiwiRail	01972-11 November 1972		In service	North Island
DXC 5039	2602	KiwiRail Phase 1	01972-11 November 1972		In service	South Island
DXB 5051	2604	KiwiRail	01972-11 November 1972		In service	North Island
DXB 5068	2605	KiwiRail	01972-11 November 1972		In service	North Island	DFT style short hood fitted.
DXB 5074	2606	KiwiRail	01972-11 November 1972		In service	North Island	2240 kW engine.
DXB 5080	2607	KiwiRail	01972-11 November 1972		In service	South Island
DXB 5097	2608	KiwiRail Phase 1	01972-11 November 1972		In service	North Island
DXB 5108	2609	KiwiRail	01972-11 November 1972		In service	North Island
DXB 5114	2610	KiwiRail	01972-11 November 1972		In service	North Island
DXB 5120	2611	KiwiRail	01972-11 November 1972		In service	North Island	2240 kW engine.
DXB 5137	2612	KiwiRail Phase 1	01972-11 November 1972		In service	North Island
DXB 5143	2613	KiwiRail Phase 1	01972-11 November 1972		In service	South Island
DXB 5166	2614	KiwiRail	01972-11 November 1972		In service	South Island
DXC 5172	2615	KiwiRail	01975-12 December 1975		In service	South Island
DXC 5189	2616	KiwiRail	01975-12 December 1975		In service	South Island
DXC 5195	2617	Tranz Rail Black ("Bumble Bee")	01975-12 December 1975		In service	South Island	DFT style short hood fitted. Derailed by a washout into the Rangitata River, January 2002.
DXC 5206	2618	Toll Rail ("Corn Cob")	01975-12 December 1975		In service	South Island
DXC 5212	2619	KiwiRail	01976-01 January 1976		In Service	South Island
DXC 5229	2620	Tranz Rail Black ("Bumble Bee")	01976-02 February 1976		In service	South Island	DFT style short hood fitted. Collided head on with DX 5235 near Middleton Yard, December 2000. 5 years later, low-speed collision after entering an occupied crossing loop at Cora Lynn.
DXC 5241	2622	Toll Rail ("Corn Cob")	01976-01 January 1976		Under overhaul	South Island	At Hutt Workshops for KiwiRail repaint & brake change
DXC 5258	2623	Toll Rail ("Corn Cob")	01976-02 February 1976		In service	South Island
DXC 5264	2624	Toll Rail ("Corn Cob")	01976-02 February 1976		In service	South Island
DXC 5270	2625	KiwiRail	01976-02 February 1976		In service	South Island
DXC 5287	2626	KiwiRail	01976-02 February 1976		Under Overhaul	South Island
DXC 5293	2627	KiwiRail Phase 1	01976-02 February 1976		In service	South Island
DXC 5304	2628	KiwiRail	01976-02 February 1976		In service	South Island
DXC 5310	2629	KiwiRail	01976-03 March 1976		In Service	South Island	Sustained major damage after derailing near Pukehou, November 1995. Took a 50km/h curve at 90km/h.
DXC 5327	2630	KiwiRail	01976-08 August 1976		In service	South Island	DFT style short hood fitted. Collision with several coal wagons, Cass crossing station, November 2008. Substantial damage to left side of cab.
DXC 5333	2631	KiwiRail	01976-03 March 1976		In service	South Island
DXC 5356	2632	Toll Rail ("Corn Cob")	01976-09 September 1976		In service	South Island
DXC 5379	2634	Toll Rail ("Corn Cob")	01976-04 April 1976		In service	South Island	due for KiwiRail repaint & brake change
DXC 5385	2635	KiwiRail	01976-04 April 1976		In service	South Island
DXC 5391	2636	KiwiRail	01976-04 April 1976		In service	South Island
DXC 5402	2637	Toll Rail ("Corn Cob")	01976-09 September 1976		In service	South Island
DXC 5419	2638	Tranz Rail Black ("Bumble Bee")	01976-05 May 1976		In service	South Island
	2639	Clockwork Orange	01976-05 May 1976	01977-03-23 March 23, 1977	Scrapped	North Island	Crashed near Newmarket, scrapped September 1978.
DXC 5425	2640	Toll Rail ("Corn Cob")	01976-05 May 1976		In service	South Island
DXC 5431	2641	KiwiRail	01976-07 July 1976		In service	South Island
DXB 5448	2642	KiwiRail	01976-07 July 1976		In service	South Island	Not upgraded to DXC (i.e. does not work coal trains on the Midland Line) due to a cracked frame, after head on collision at Waipahi 1999.
DXC 5454	2643	KiwiRail	01976-05 May 1976		In service	South Island
DXC 5460	2644	KiwiRail	01976-07 July 1976		In service	South Island
DXC 5477	2645	KiwiRail	01976-06 June 1976		In service	South Island
DXC 5483	2646	KiwiRail	01976-07 July 1976		In service	South Island
DXC 5500	2647	Toll Rail ("Corn Cob")	01976-08 August 1976		Under overhaul	South Island	Locomotive caught fire while on a freight duty near Rolleston, 12 January 2012.
DXC 5517	2648	Tranz Rail Black ("Bumble Bee")	01976-08 August 1976		In service	South Island
DXC 5520	2603	KiwiRail	01972-11 November 1972		In service	South Island	Formerly DX 5045. Renumbered after returning to service following fatal derailment at Te Wera in 2002. DFT style short hood fitted.
DXR 8007	2633	KiwiRail	01976-04 April 1976		In service	South Island	Formerly DX 5362 rebuilt 1993 & 2006
DXR 8022	2621	KiwiRail	01976-01 January 1976		In service	South Island	Formerly DX 5235 rebuilt 2003

See also

• South African Class 34-000
• South African Class 34-400
• South African Class 34-500
• South African Class 34-900

References

Books

• Parsons, David (2002). New Zealand Railway Motive Power 2002. New Zealand Railway and Locomotive Society. pp. 64. ISBN 0908573780. http://www.railsoc.org.nz/pub/books.htm.