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The New Zealand Railways Magazine, Volume 1, Issue 2 (June, 1926)

Train Diagrams: Their Practical Application

page 20

Train Diagrams: Their Practical Application

Train diagrams are in general use throughout the world in connection with train running work. They are an essential part of the equipment of timetable offices. As it is probable that many members of the staff who have not been in touch with such offices are not acquainted with these graphs a reproduction of a train diagram for the Frankton-Ohakune Section is printed in this number.

The diagram is divided by vertical lines into 24 equal spaces representing the 24 hours of the day. Each of these 24 spaces may be sub-divided into spaces representing 30, 15, 5, or less minutes as found desirable.

The names of all stations where crossing loops are provided are shown at the sides of the train diagram in station order and at a distance from each other in proportion to the actual mileage between the stations. A horizontal line is drawn across opposite each station name.

The forms being ruled as shown, the next procedure is to insert lines to represent the trains. The timetable is taken and the trains are plotted on the diagram in timetable order.

Suppose that No. 115 Down Daylight Limited Auckland to Wellington is being dealt with. This train leaves Frankton at 10.22 a.m., Ohakune arrive 3.55 p.m. The line representing No. 115 commences at the horizontal line opposite Frankton and at the vertical line representing 10.22 a.m. It runs to Rukuhia 10.31 a.m. Te Kawa 11.5 Otorohanga 11.17 and so on to Ohakune, finishing at the intersection of the horizontal line opposite Ohakune and the vertical line at 3.55 p.m.

Similarly in the case of an up train, say No. 684 Up Daylight Limited Wellington to Auckland, the line for this train starts from the intersection of the Ohakune horizontal line and the vertical line at 3.22 p.m. Horopito 3.39 Kakahi 4.49 and so on to Frankton where it finishes at the intersection of the Frankton horizontal line and a vertical line representing 8.26 p.m. It will be observed that the line representing the down trains (odd numbers) run downwards while those representing the up trains (even numbers) run upwards, but both slope towards the right (the close of the day).

The lines denoting the trains must cross at one of the horizontal lines because these indicate the crossing sidings. In the few cases where the lines cross away from the horizontal lines the trains represented run on different days of the week and so do not cross. An example of this will be seen in the top left hand corner. No. 430 runs on Sunday only, and, as No. 243 does not run on Sunday, these trains do not cross.

The following are some of the points clearly shown by the train diagram:—

Whether trains are timed uniformly.

Where trains cross and where they pass. (No. 684 Up Daylight catches up and passes No. 244 at Te Kuiti at 7.15 p.m.).

Whether timed to follow each other too closely.

Whether times fit at crossing stations.

The density of the traffic on the section and at particular stations.

The hours staff are required to be on duty.

Where intermediate crossing places would be an advantage. (Note the long section between Poro-otarao and Puketutu.)

Where the work of a goods or mixed train requires regulation to avoid delay to a following fast train.

Connecting trains.

Where pick up or set down trains are provided. (No. 244 Taumarunui depart 4.15 p.m. is a pick up train for No. 684 Up Daylight as far as Te Kuiti. No. 413 Frankton depart 6.50 a.m. is a pick up train for No. 115 Down Daylight.)

It will be noticed that the section illustrated by this graph is occupied almost continuously during the whole 24 hours. The diagram gives a birds-eye view of the whole service on that particular portion of the line. It is very useful in arranging the runs of engines and trainmen. If a special train is required a glance at the diagram gives an indication as to where a clear track can be obtained. Any variation from the straight of a line denoting a train immediately catches the eye and indicates whether the train is travelling faster or slower than normal speed. Note the slowing up of the Down Daylight on the steep grade from Te Kuiti to Porootarao.

This class of work is a specialised one and considerable practice and experience is necessary to attain full efficiency. It is hoped that the diagram printed in this issue will stimulate interest in this branch of the work.

page 21
Train Diagram: Main Trunk-Frankton-Okahune

Train Diagram: Main Trunk-Frankton-Okahune

page 22

Training of Apprentices

The future welfare of our railway engineering organisation depends in a great measure upon the engineering capabilities and education of the apprentices of to-day, for we have to look to these lads to fill the executive positions in the Service in the future. The three avenues of instruction to apprentices that have to be considered are (1) Personal, (2) Practical, (3) Educational.


The majority of the boys who commence their career in the Railway Service as apprentices have had no experience of the particular trade to which they are indentured, and in such instances it behoves the foremen and leading hands individually concerned carefully to view the efforts made by each boy to master the daily problems he is confronted with. If, in the opinion of the officers concerned, a boy is doing his utmost, it should be the province of his superior officer to acknowledge the effort and take a personal interest in the progress of such apprentice by tendering sound advice as to behaviour, workmanship and education.


Generally speaking, the practical training afforded the apprentice in our workshops may be considered good. An all round knowledge of machine tool work is incorporated in conjunction with the practical training, and it should therefore be the aim of our foremen and leading hands to place the apprentice who has evinced a definite desire to master his trade, with the most competent tradesman who is temperamentally suited to act as instructor.


During the past five years the Department has granted monetary remuneration to those apprentices who have attended technical colleges in their own time and secured the requisite diplomas. This, however, has failed to stimulate apprentices to attain the necessary educational qualifications. It is also a moot point as to whether the instruction offered in such colleges has been of very material benefit to such apprentices.

The Department has decided to give all apprentices at least three hours instruction per week in departmental time. This is a move in the right direction, and I would appeal to all tradesmen to foster the movement to the utmost of their ability. The apprentices should avail themselves also of this avenue of knowledge afforded them by strict application to their work and studies. The aim of the management is to assist in maintaining the present high standard of workmanship set by our leading tradesmen.

It is a well known adage that “Competition makes for progressiveness” and the educational programme in view will probably lead to competitive examinations at six monthly or twelve monthly intervals. The ideal would be to afford those apprentices who attained the highest marks an opportunity of acquiring further knowledge at an Engineering College, or in the alternative, experience abroad.

The Department has the interests of the apprentices at heart, and every railwayman should assist the educational proposals to the utmost of his ability. Apprentices should embrace every opportunity of improving their knowledge mental and manual.

Locomotive Firing Methods

In the course of a lecture recently delivered by Mr. James T. Hodgson at a meeting of the Railway Locomotive Men's Craft Guild at the College of Technology, Manchester (says the Railway Gazette, 12/2/26), reference was made to the automatic manner in which the locomotive draught is varied according to the load on the engine. The author further stated that the fuel on the fire-bed could also be regarded as a draught regulator, in that the rate at which the air passes from the ash-pan through the bed of fuel can be determined to a certain extent by the size of the coal and the thickness of fire-bed carried. In other words, the thin portion of the fire-bed offers less resistance than the thicker portion; hence, if the fire be carried too thin against the fire-box plates, this portion of the fuel provides the path of least resistance, and an excess of air passes through these portions of the fire grates. The best methods of firing were accordingly said to be those which prevent recurring damping effects, as when coal is fired in too large quantities, or chilling effects, as when air is allowed to pass in excessive quantities through the thinner portions of the fire-bed. The endeavours of the firemen, should, therefore, be concentrated in an effort to maintain a uniform depth of fire-bed, which should be slightly thicker against the fire-box plate and to maintain the highest fire-box temperature obtainable irrespective of the demands for steam. Considerable skill is required in firing a locomotive, especially when working under difficult conditions, the object aimed at being to obtain the maximum number of heat units as the demand for steam increases, and to maintain a high fire-box temperature without blowing off at the safety valves.