1918 19th Century On the Land Electricity Iron Sands to Steel Think Big

The Wonders of
Cheap Hydro

Plumbing of Steam
Main Line
Cook Strait Cable
Evan Parry


 "As soon as the limits of steam haulage have been reached on some critical section of the Main Trunk say between Taumarunui and Taihape – that is to say when no more traffic can be conducted over it in spite of the utmost possible improvements in track and locomotives, strengthening bridges, increasing the number of passing places and so on – and the traffic continues to increase then the railway management will be faced with the necessity of extensive re-grading and deviating and later on of duplicating the line.  If at this juncture an adequate supply of electric power were available the same result would follow as in other similar cases – viz the Railway Department would adopt the most economical solution of the problem and electrify the section or division in question."

Evan Parry: New Zealand Journal of Science and Technology. Volume 1 November 2022

Parry’s logic was impeccable, but it was not until sixty-two years later that the Minister of Railways announced Government approval for the electrification of the North Island Main Trunk Railway over the difficult central section between Hamilton and Palmerston North.

The Most Important Rail Link

Of all railway routes in New Zealand, the North Island Main Trunk (NIMT) is easily the most important; it carries over one third of all traffic and much of this is on through trips between Auckland and Wellington. Because of the least cost philosophy adopted in its construction, and as a natural consequence of the terrain it passes through, the line is characterized by steep gradients and curves.  Except between Auckland and Hamilton there is a single track.

The Main Line Electrification Story illustrates the dilemma that arises when a government without close knowledge of a topic must make a major technical decision and advisors cannot agree because they have conflicting agendas.  A likely scenario in this situation is that no decision is made.  Another example of this was with the Cook Strait Link. .


A Visionary General Manager

The spirited advocacy of F.W. Aicken, then General Manager of the Railways Department, nearly led to North Island Main Trunk line electrification in the nineteen-fifties but his visionary ideas were in conflict with those of his engineering staff.

After the Second World War, the Railways had great difficulties in providing a service. The root cause was staff shortages. In the post-war boom, skilled staff were lured away by attractive opportunities elsewhere in the economy.  In 1950, despite active recruiting campaigns, there were 3,350 staff vacancies.

Considerable overtime working took place on the track and in the workshops but it was necessary to postpone steam locomotive overhauls beyond the specified mileage and this led to reduced locomotive availability. Coal shortages were also frustrating. These were alleviated by imports from South Africa, and speeding the conversion of coal-fueled locomotives to oil-burners.

F.W. Aicken had been appointed General Manager in 1948. He had previously been Staff Superintendent and Chief Legal Advisor to the Department. Buying diesel-electric traction for the expresses on the North Island Main Trunk was thought to be too expensive. Aicken then turned his attention to electrification, mainly because be saw that it could relieve the coal situation and prevent high expenditure on imported fuels.

As he got into his study, he came to see that electrification had many advantages and he began to regard it as the salvation for the railways; "an instrument by which the ills and deficiencies of railway transportation…. may largely be cured.”

He learned from one of his technical staff that an alternating current (AC) system could be cheaper than the 1,500 DC system which would have followed from departmental practice, and sent a technical mission of four senior officers overseas in March 1949. Their brief was to determine the most suitable system of electrification.

A Tentative Contract

Aicken travelled overseas himself and negotiated a tentative contract with a British construction company. After the travellers had returned to New Zealand, a senior staff conference decided to opt for the AC system. The Chief Mechanical Engineer and Chief Accountant specified and costed the system and Aicken was able to complete a substantial report justifying the NIMT electrification and submit it to the Government.

Officers from Treasury and the Ministry of Works, and also two experts from Sweden, where electrification had a long history, produced comment on the proposal (Messrs Thelander and Edenuis). 

Eventually, in December 1950, the Government granted approval in principle and agreement to appoint Thelander as a consultant.

In the meantime, in September, because engine power was getting short, after consultation with Treasury, Aicken ordered 31 diesel-electrics and 16 JA steam locomotives for main line work. Aicken, who was reportedly not in sympathy with the National Government, retired from his position as General Manager in July 1951 and with the change in regime the electrification proposal disappeared.

A Royal Commission Provides a Forum

It became public the following year that there had been dissension in the ranks in the Department.  A Royal Commission on the Railways was held because the organization was still in trouble; a large loss had been made, morale was low, annual leave was being postponed, and long hours worked. In a short time fuel oil prices had more than doubled to a price in real terms not greatly different from that of 1980, and competition from road transport was increasing.

Electrification was not one of the Commission’s main concerns. It heard evidence on it but ducked the issue, saying in its report that a wide divergence of opinion existed but that, as the Commission was itself not technically qualified to judge, it could not express a worthwhile opinion.

What the Royal Commission did do was reveal that Aicken’s successor, H.C. Lusty, previously the Chief Civil Engineer, did not share Aicken’s enthusiasm for electrification.

Aicken admitted to the Royal Commission that Lusty had not supported his proposals but told it that R.F. Black who, as Chief Mechanical Engineer, had favoured the use of diesels on the NIMT in front of the Commission, had not spoken out previously against electrification and had contributed to Aicken’s report.

It seems very likely that Lusty and Black, as technical people, disapproved not only of Aicken’s decision but his manner of reaching it.  He seems to have made an early choice in favour of electrification, seeing in its adoption cures for many of the Department’s ills. The mission he sent overseas was given the task of choosing an electrification system rather than a broad brief to investigate systems of locomotion for the NIMT route.

Aicken’s Report

The Commissioners received Aicken’s report. It is a discursive document of some 180 pages; clearly not the work of a technocrat, nor that of a committee, but the broad-ranging findings of a visionary with a full understanding of the Department’s workings who thought he had the answer to many of its problems. The flavour can be gauged from some of the section titles:

*    -2.Past Bold Railway Projects in Retrospect

*    -5."Main Trunk" Vital to New Zealand’s Economy

*    -6.Transport is a Social Problem and Railways are Vital to our Existence.

*  -13.Fuel supplies – Striking Economic Factors.

*    -14.Half-Measures Unsound and Impracticable.

*    -18.Are Electric Railways Vulnerable in War.

A key factor in Aicken’s case was the proposition that, by1961, traffic on the NIMT expressed in gross ton-miles would be 50% greater than that in 1949. This figure was a linear projection of the trend in traffic growth from 1929.

Aicken argued that electrification of the North Island Main Trunk would, in effect, cost nothing. If the route was electrified instead of buying new steam locomotives to meet the increased traffic, the savings in operating costs would, within nine years, more than offset the much higher capital requirement of the electrification scheme.

"It will be a beneficial factor in the advancement of the Dominion. There are many things which electrification can achieve.  Each benefit which it confers brings on another and that benefit, in time, produces others."

He then listed what he thought electrification had the power to do including:

Ø      —-   Improving the service,

Ø      —-   Curbing inflationary costs,

Ø      —-   Removing reliance on imported fuel,

Ø      —-   Cutting expenditure of sterling funds, improving railway patronage,

Ø      —-   Solving to a large extent the manpower shortage in locomotive running and the workshops,

Ø      —-   Reducing the numbers employed by the Public Service,

Ø      —-   Reducing the land area occupied by the Railways,

Ø      —-   Producing better working conditions for the staff,

Ø      —-   Making the rail system better able to meet the demands of war,

Ø      —-   Ridding the cities of grime soot and smoke and fumes and of unsightly engine depots,

Ø      —-   Enabling the Railways Department to grant leave when it became due, and

Ø      —-   Eliminating the need for costly civil engineering works

Aicken did not overlook diesel-electric locomotion but he argued against it. It was only within the past three years that a British manufacturer had designed and produced a traction-type diesel for main-line working and difficulty had been experienced in producing a high powered locomotive within the limits of the British loading gauge.  (At that time New Zealand was in the sterling area, buying British was important). In North America, in contrast to Europe, diesel designs had been developed and widely adopted in the post-war period but there they had relatively cheap oil.

Apart from involving the danger of reliance on a foreign source of fuel, diesels were complex, requiring highly skilled maintenance staff more readily available in a heavily industralized country.

Aicken showed that, economically, diesel-electrics could not compete with electrification if traffic was to grow by 50% by 1961. Since a diesel-electric locomotive was in fact a travelling power station, the savings through electrification compared to diesel could be regarded as the difference between the cost of buying in bulk electrical energy generated substantially from New Zealand resources and the cost of generating electricity in small plants using imported diesel fuel.

An Idealistic Solution

Economic arguments aside, and at the risk of oversimplifying the issue, electrification could be regarded as the idealistic way of providing locomotion for the North Island Main Trunk and the purchase of diesel-electric engines the pragmatic. Electrification involved a high capital expenditure along the track while diesel locomotive costs and running costs would be higher. Each showed clear advantages over steam because of higher efficiency of fuel use, lower operating and maintenance costs and reduced manpower requirements.

When R.F. Black, the Chief Mechanical Engineer, presented his evidence to the Royal Commission, he said that undoubted economies could be achieved by using diesels on the Main Trunk and in the southern half of the North Island.  Any available capital should be directed to this purpose.  Major electrification should then be considered, taking into account all factors.

Aiken though Retired Gives Evidence

It was this evidence and his comments under cross-examination that diesels should have been purchased in 1948 that prompted Aicken, now retired, to himself produce evidence and appear before the Commission.  He outlined to it the history of his electrification proposal and his fear that, through postponement of it, the chance would be lost because other types of traction would be purchased.  He requested that the Commission should order that his reports and any others be made public and that, in the event of any adverse report, he should have right of reply.

Under cross-examination he said that to use diesels was a short-term policy, in his opinion a lazy man’s answer.  When he had ordered diesels and further steam locomotives in 1951, it had been as an interim measure, because the Government had not made the electrification decision.

Support for Aicken came in evidence given by the New Zealand Railway and Locomotive Society, a rail enthusiasts’ group. It emphasized the high power-to-weight ratio and energy efficiency of electric engines and the strategic importance of a home-produced power source.

Lusty has the Last Word

 Lusty, the new General Manager, had the last word. He made a second submission to the Commission saying that it had not been intended that the Commission should subject Main Line Electrification to detailed examination, "however, certain events have made it desirable that I should at this stage make a statement on the position."

On assuming office he had wished to review the electrification proposals.  However, because of pressure of work, he was not in a position to make a final recommendation.  He was not prepared to proceed with the proposal from the British company with whom Aicken had negotiated to do the overhead line erection and other work.  It contained terms quite unacceptable to him. Besides, it was clear that the cost would be substantially higher than had been suggested, not lower as stated by the Swedish experts.

Because of the locomotive purchases which had been made, it was not possible to claim, as had Aicken, that there would be a credit for non-purchase if electrification proceeded.  There had been locomotives released by the electrification of the Hutt Valley and Auckland lines and diesels previously purchased for shunting were more suitable for main line work. In any event, there was nothing to justify the traffic growth that Aicken had estimated. Very careful examination by his officers suggested that 1961 goods traffic would only be 35% higher than the 1949 level.

Recent experience had shown that, with the addition of an engine turning triangle at Kakahi, it was possible to deal with a volume of traffic on the difficult Taumaranui-Ohakune section 40% above the 1949 peak.  After taking into account all factors, sufficient locomotives were on hand or on order to cover the estimated requirements for another ten years.

Although he said he was not in a position to make a final recommendation, Lusty had clearly made up his mind.

 He went on to discuss the economics of dieselization. In March 1951, the Electromotive Division of the U.S. General Motors Corporation had presented a report that said only 61, not 121, diesels, as claimed by Aicken, would be needed on the North Island Main Trunk, and that the savings in annual costs would be £940,000 compared to electrification. While he was not prepared to accept this statement, pending a thorough investigation into the matter, "the estimates are not likely to be any more optimistic than some other figures, referred to earlier, which appear to be completely unreal." This General Motors report was received by the Railways Department before Aicken retired.  It is not clear whether he knew of its existence. The pro-diesel advocates may have solicited it.

Not content that he had made his case with all this evidence, Lusty then went on to point out that the diesel oil requirement of the railways of about 20,000 tons was very small compared to the country’s imports of oil products of 900,000 tons.  There was little evidence of concern with road traffic dependence on imported motor spirit.

Senior branch controlling officers had not had the opportunity to comment on the electrification proposals.  He could definitely say that, if they had, they would not have recommended that electrification proceed.  Finally, there was ample time to consider electrification and alternative schemes.  He would like to see an investigation carried out by senior officers without undue haste, and without the influence from outside which had been evident in respect to the electrification proposal.

Heroes  & Villains

Who was right? In railway histories by Gordon Troup and Bill Pierre, Aicken is the hero and Lusty and his supporters the villains.  Troup talks of those who held up electrification retiring to lucrative posts representing oil companies or diesel manufacturers.  Pierre in his study of the  North Island Main Trunk refers to Lusty’s inability to differentiate between urgency and mere haste, and points to the large number of new diesel locomotives he was forced to order in 1954.

In retrospect, credit must be given to Lusty on two counts. Firstly, traffic growth to 1961 was much less than Aicken had predicted (it is dangerous to simply project growth trends over a large time span as electricity planners were to find); secondly, a lengthy period of good availability and reducing real price of oil lay ahead. A factor, which must have weighed against Aicken’s proposal, was that it involved high initial capital expenditure. This would have militated against it with Treasury officers and Ministers attempting to choose between competing claims on capital.

Go Ahead in 1980

The electrification proposal which received approval in1980 had its genesis in a study group set up in June 1974 to report on measures to be taken to cope with increasing rail traffic volumes.  This led to a technical study carried out with assistance from the Japan Railway Technical Service, and then to an Interdepartmental evaluation, which considered whether it was a worthwhile investment from the nation’s viewpoint.

Advantages and Disadvantages

Although these studies would have been more sophisticated than in 1950, and the existing locomotives were diesel and not steam, the advantages of electrification remained those put forward by Aicken in 1950. It increases track capacity because it is faster and more powerful. Whereas a diesel locomotive can haul 720 tonnes at 27km/hr on the Raurimu spiral, an electric locomotive hauls 1100 – 1200 tonnes at 45km/hr, cutting 3-5 hours off journey times.

Less fuel is needed and employing regenerative braking lowers the fuel consumption further.  This means that in braking situations, such as going down grades, the motor can be run as a generator, the power produced being fed back to the system..

Compared to diesel the locomotives are cheaper, have long life and, being less complex, have greater reliability.  Grade easements are not required on the track.

Disadvantages are the high basic capital cost, the possibility of electrical hazards, the visual intrusion of the overhead system and electrical interference with communication systems.

Without safeguards this latter problem could affect both railways communication systems and those of the Post Office.

Electrification’s advantages were reflected in the economic evaluation, which showed a rate of return of 18% in the study of the Palmerston North-Te Rapa (Hamilton) section.   Sensitivity analyses showed that this high rate of return gives the project robustness against changes in traffic volume less than expected, (the return remains positive if traffic falls), against significant increased in construction cost, and against lower than expected rises in the diesel fuel price.

The complexity of the project and its capital intensiveness are reflected in the design and construction time.  Commercial use of the 411km electrified between Palmerston North and Te Rapa began in June 1988

An overall cost in excess of $100 million had been projected, with some 40% being for the locomotives, but the final cost was about $250 million.

Curve Easement

An interesting result of the electrification decision is that restrictions on speed are caused by curves rather than grades.  Thus to take full advantage of electrification the Railways Corporation has undertaken a curve easement programme even where in some places this leads to an increase in grade.


Earlier Electric Schemes

We must not overlook the fact that certain parts of the rail system are already electric.  The steep Arthur’s Pass-Otira section with the long Otira tunnel opened in 1923. (The choice of electrification system for this venture was the responsibility of J.E.L. Cull, Evan Parry, etc. Evan Parry, then chief engineer of English Electric, visited New Zealand to be present at the opening).

Ventilation problems with steam trains and a long tunnel led to electrification of the Lyttleton-Christchurch line in1929; it remained electrified until 1972, when diesel took over.  In the Wellington region, grades, tunnels and traffic density led to the electrification of the Wellington-Johnsonville (1938) and Wellington-Paekakariki lines and traffic density justified the conversion of the Wellington-Hutt Valley section.  These are direct-current systems. 

As proposed by Aicken, for the NIMT the system is high voltage alternating current.

No other main routes are at present considered likely to develop the traffic densities that would justify electrification.


Troup,  “Steel Roads of NZ: One Railway (1950 -1972)"       pp 198 – 210     

Pierre, "North Island Main Trunk", Reed, 1981.

-Evidence presented to Royal Commission on Railways – Submission no 165.

Aicken –Electrification report.

 Royal Commission notes oil price increase from 8 pounds 19 shillings to 21 pounds (per ton) Appendices to the Journals of the House of RepresentativesD-3 p11 1952.  


The Most Important Rail Link
A Visionary General Manager
A Tentative Contract
A Royal Commission Provides a Forum
Aicken’s Report
An Idealistic Solution
Aiken though Retired Gives Evidence
Lusty has the Last Word
Heroes & Villains
Go Ahead in 1980
Advantages and Disadvantages
Curve Easement
Earlier Electric Schemes

Coal Shortages



Aicken was not in sympathy with the National Government

A discursive document