The New Zealand Railways Magazine, Volume 3, Issue 9 (January 1, 1929)
Modern Methods in our Workshops
A far reaching improvement upon the old method of weighing locomotives at Hillside Workshops has been introduced through the ingenuity of a member of the local staff. As described in the following article, locomotives can now be weighed in two hours instead of eight, as hitherto.
AMost important aspect of locomotive engineering is that associated with the weighing of locomotives before they are put into commission on the active service list. The object of weighing a locomotive is to ensure that each driving and bogie wheel of the great machine carries its proper share of weight. Unequal distribution of weight means loss of tractive power, and where sections of heavy country have to be negotiated this factor is of vital moment. The question may be asked: “How is a locomotive weighed?” It is weighed on specially designed weighing machines. These machines, though unimpressive in appearance and very simple in design, are, nevertheless, remarkably efficient, and register the weights of the respective parts of the locomotive with the greatest accuracy. In cases where a locomotive has undergone repairs of a nature likely to have caused a change in the weight distribution, the closest attention is paid to the weighing operation, adjustments and re-adjustments of the spring gear of the locomotive being made until the weights are correctly proportioned. The locomotive weighing machine embodies the principle of the lever, the machine being, in effect, but a series of levers.
By way of digression, it is interesting to observe that the principle of the lever dates from the very dawn of history. Levers were used by the ancient Egyptians in the construction of the Pyramids, and, right down the ages, they have been more or less intimately associated with mechanical contrivances.
Illustration No. 1 depicts the type of weighing, machine originally used by the Railway Department. This machine was of the straight-out suspension lever type with a graduated arm and weight, and was considered quite effective in its day. Modern developments, however, produced a more effective appliance, as shown in illustration No. 2. It will be seen at a glance that the machine featured in the latter illustration is much more efficient in design, giving greater scope and a finer and more accurate adjustment. It has, moreover, the important advantage of occupying less space when in position.
One of the main features of the new workshops scheme is the provision of ample working room. In the design and lay-out of the weighing pit of the new locomotive erecting shop at Hillside the importance of this factor has, therefore, been given full recognition.
Under the old conditions the handling, placing in position, setting up of the machines and weighing of the engines, was a laborious process. Owing to the lack of space it was necessary to store the weighing machines on shelves between the columns of the buildings, and they were lifted to and from these shelves by an appliance suspended from the overhead crane and then placed in position under the wheels of the engine to be weighed. The average time occupied in weighing an engine under these conditions was eight hours.
Much consideration was given to the matter of effecting an improvement on these cumbrous methods in the new shops, and, as the purchase and installation of a special weighbridge could only be done at prohibitive cost, ways and means of utilising the present machines were sought.page 41
The problem was ingeniously solved by a member of the Hillside staff. A special pit was laid down and the necessary alterations to the weighing machines effected, with the very gratifying result that an engine can now be weighed in the new shops in two hours—a saving of six hours over the old method. Moreover, results are obtained equal in accuracy to the most elaborate weighbridge.
In the construction of the new weighing apparatus at Hillside a shallow pit was excavated on each side of one of the steaming tracks which is set aside for weighing locomotives. Two rails, set in concrete parallel to the track, were installed in each of the shallow pits, and plate carriages were made to travel on these two sets of rails. Wheels were mounted on the base of each weighing machine. These wheels engaged on short runners affixed to the top of the plate carriages mentioned. Thus, by this arrangement, the weighing machines can be easily moved, parallel with the locomotive, to suit the different wheel centres of the various types of locomotives. The machines can also be moved in and out at right angles to the locomotive—under its wheels.
Great care was necessary in the installation of the weighing machines in order to obtain perfect alignment. Up to date, several engines have been weighed, and the new installation has proved highly efficient, handling time being reduced to a minimum, and vexatious delays altogether eliminated.
The installation of the new machines is a notable step forward in the equipment of the workshops for increased production, through which the Department and the Dominion generally must benefit.
On Fire Extinguishers.
The workman who never makes the opportunity to notice positions of the nearest fire extinguishers when he doesn't need them may not have a very good opportunity to do so when he suddenly does need them.