ViTrains Class 37 Diesel Locomotive Bogey Removal


Tips 'n' Tricks


Tips'n' Tricks No.1: Removing & Dismantling A ViTrains Class 37 Diesel Locomotive Powered Bogie



Re-Liveried Vi-Trains Class 37/4 No. 37429 'Eisteddfod Genedlaethol'

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DISCLAIMER: This document, the acts of work and the methods described herein are merely a guide and should be treated as just that. Should you as an individual decide to follow any or all of the steps or work as outlined or described herein, or follow any specific section as written, you do so at your own risk. Should you follow this guide, you agree that we (the writers and publishers of this document) shall not, will not and can not be held liable for any injury or damages that may be caused to yourself, your own or another persons property or personage.

Before starting, please note that this guide assumes that the body of the model locomotive has been removed and therefore, if this is not the case, reference should be made to any documentation available that indicates how this is achieved. The aim of this "how-to" is to show the dismantling of the powered bogey of this model locomotive in preparation to exchange the traction tyre afflicted wheel-set such that this be required by an individual modeller. Many people prefer to do replace traction tyre fitted wheel sets to ease maintenance time & cost as well as improve overall prototypical appearance. One difficulty that is often overlooked however, is that some traction may be lost and it is left to the individual to test haulage capability before switching wheel-sets in order that a "benchmark" capability is noted. This "benchmark" will enable a post wheel-set replacement haulage test to take place with a known haulage capability. It is also worth checking for traction loss (wheel slippage) as an all metal wheel will slip sooner than a wheel fitted with a traction tyre. If needed, extra weight may be added in the form of lead to help aid traction, yet care must be taken in how and where this extra weight is added especially with a printed circuit board (PCB) present inside the body.

Step 1: Removing The Bogey From The Chassis

Before we attempt removal of the bogey unit, attention must first be paid to ease of access. The easiest method to access the bogey retention clips is to remove the seat/cab rear moulding (Fig.1). This is held in place by a phillips (cross) head screw. Once this screw is removed, lift away the seat/cab rear moulding and place to one side. Replace the screw from whence it came to avoid losing it. Now that we can see what we are doing, we can clearly see that there is a retaining lug integrally moulded to the gear tower at the front (there is also one to the rear). It is easiest if the front clip is gently eased backwards while easing the bogey unit downwards , whilst also paying attention to where the carden shaft is. Once free from the chassis, the bogey is still tied to the PCB via the two current carrying wires headed from the bogey pick-ups(Fig.3). You will also have the carden shaft (or propeller shaft) to place in a safe place to avoid loss until the bogey unit is refitted. The photographs below will aid this description as well as give a visual aid to the task at hand with captions aiding the photographs also.

Whilst every effort is made to avoid creating work, given the constraints caused by the short pick-up wires from the bogey, it may be far easier for some modellers to unsolder these same wires from the PCB. If this path is taken, notes MUST be made of which wire goes to which solder pad on the PCB. This is especially important to avoid causing a short circuit.

Fig.1	Fig.2	Fig.3	Fig.4	Fig.5	Fig.6



Step 2: Removing the Bogie Frame & Releasing The Gear Tower

This is quite an easy task, yet care must be taken to avoid damage being caused to any detailing parts, more specifically, the fragile brake "rigging" of the bogey frame as well as any of the "extra" detailing parts that may have been fitted. The removal of the bogie frame is noted in the captions on the photographs below as it is far easier to show a picture with a description than use mere words to describe the process involved.

Fig.7	Fig.8	Fig.9



Step 3: Refitting The Bogey wheels & Bogey Frame To The Gear Tower (Or Visa-Versa)

Now we are at the stage of re-fitting the wheel-sets, we are approximately half way through the task at hand. The easiest way to get this pat of the job completed, is to first pinch the current collecting "pick-ups" in, towards the body of the gear tower. A geared wheel-set is then dropped into it's guide at the outer end with the pick-ups acting on the integral channel on the rear face of each wheel. The following wheel-set to be fitted is the second geared wheel-set, followed by the centre (non-driven) wheel-set. With this done, the bogie frame is laid atop the gear tower and wheel assembly in such a way that the forward end of the frame is pointed in the opposite direction that the drive cup is pointing. The photographs below will clarify this, as will the helpful captions that are included to the bottom of the photographs.

Fig.10	Fig.11	Fig.12	Fig.13




Step 4: Refitting The Bogey To The Chassis

Re-fitting the bogey unit to the chassis is not quite as straight forward as it may seem. The use of the carden shaft makes things a little interesting to say the very least so to make things a little easier, we remove parts to aid refitting the bogey. Taking the bogey as it stands, we remove the "cap" that retains the worm gear (Fig.14), which leaves us with what is shown in Fig.15. Next, the drive shaft is removed (Fig.16) before we refit the bogey inserting the rear (inner-most) end into the chassis first to locate the rear retaining clip (Fig.17). This is where the "fun" begins. Fig.18 through Fig.24will guide you through the remaining steps to completion of this how-to and thus the completion of the work required

Fig.14	Fig.15	Fig.16	Fig.17	Fig.18	Fig.19



Fig.20	Fig.21	Fig.22	Fig.23	Fig.24



With the re-soldering of the wires, the work is completed. Do not forget to give the locomotive a quick test, either on track or on a rolling road to ensure that everything is functioning as it should do. There is nothing worse than finishing the rebuild of a locomotive only to find under testing that it requires a further strip down to correct a fault that would have been detected if it had been tested prior to re-fitting the body.



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