Class 25 High Level Loco 2019
by David Osbourne
Shortly after Christmas I was approached by Mark Dale who asked me if I would be interested in building a 5” gauge locomotive for use on the raised track. As I had just completed my latest project, I agreed to build a class 25 diesel outline locomotive using a kit supplied by Maxitrak.
I took delivery of the kit of parts in early March and promptly set about tackling the project. My first task was to identify the various components from a list of some 230 parts, (not including the 850 off 1.2mm diameter brass rivets). The main components consisted of a folded steel chassis and a one-piece GRP body. Having checked the fit of the body on the chassis and cut it out to ensure a good fit, I then sanded the body moulding using “wet and dry” abrasive paper. The body was then put on one side while the chassis was assembled.
The assembly of the two bogies was next on the agenda. The locomotive is powered by eight 60-watt high torque motors, two motors on each shaft to set up the bogies it was necessary to fit the wheel sets to the bogie plates having first soldered the leads to each motor, checking that the motors all rotated in the same direction. The “cosmetic” details were then added to each bogie and the completed units bolted to the chassis.
The locomotive controls consist of a 4QD electronic speed control unit and a horns and lights auxiliary relay board. Although the wiring diagram indicated the latter operating on twelve volts, I decided to wire the whole locomotive from a twenty-four-volt supply. In order to achieve this, it was necessary to obtain two twenty-four-volt horns, as “Maxitrak” could only supply twelve-volt units. In order to enhance the model an attempt was made to purchase a sound system. However, a unit with the authentic sound of a class 25 diesel was not available. In the meantime, I was aware that Clive Burrows was in the process of building a sound system for his class 66 diesel outline locomotive using his vast knowledge of electronics. I approached Clive to see if he would be prepared to build a unit for the class 25 locomotive, to which he agreed. Having downloaded the authentic sound from various sources he worked on the sound system. The layout of the controls included an eight-ohm speaker in readiness.
Returning my attention to the locomotive body, I proceeded to cut out all the window openings using a small cutting disc and a Dremel drill, a task that I find very tedious. With all the window openings cut out, I could start to prepare the body for painting. In order to fully utilise the “super detail” kit including the various water slide transfers, I decided to adopt the livery used by “Maxitrak” in their instruction manual, i.e., two-tone green. I am well on with the painting process, and, by the time this article is printed, I should have completed the task, leaving only the windows to cut out of sheet Perspex and fix in place.
By the time I return from a short break in early May I should be nearing the completion of the project, certainly by the time of the AGM. In general, I have attempted to make the locomotive as user friendly as possible, including the charging of the two twelve-volt batteries. In order to avoid the isolation circuit which is incorporated in other electrically operated locomotives operated by the Society, I have opted for utilising the main circuit breaker for this purpose. I have located the breaker immediately under the roof of the loco, and I have incorporated a lift-up flap to access the same, suitably disguised to look like the other hatches in the roof moulding. This will alleviate the need to remove the body. This lift-up flap is illustrated in the attached photographs.
On Sunday 23rd June 2019 the locomotive was completed and handed over to the society for use on the high-level track.