Heljan ex-GWR 43xx Mogul Modifications


This modelling project describes a few detailing modifications to the Heljan 7mm scale ex-GWR 43xx Mogul locomotive.


Background


The Heljan Model as supplied


As supplied, the Heljan model is simply superb. However, there are a number of enhancements which can be made to make an already superb model even better:

  • Adding extra weight and sound deadening to the tender
  • Preventing the knocking sound cause by slack in the loco/tender coupling
  • Fitting coal in the tender
  • Painting the tender wheel rims
  • Painting the pony truck wheel rims
  • Painting the front pony truck axle
  • Fitting the AWS equipiment
  • Remounting the smokebox number plate
  • Applying light weathering


Adding extra weight and sound deadening to the tender

Because this loco only has pickups on the tender, there is a need to ensure better electrical continuity with the rails by adding further weight to the tender.
The tender itself has a substancial plastic body which also acts as a little bit of a sound echo chamber when the loco runs.
Both of these issues are easily resolved by adding further weight inside the tender:


Preventing the knocking sound cause by slack in the loco/tender coupling

A common problem which affects models in many scales is the coupling between a loco and its tender. Typically, some kind of bar is used which has holes through which either screws or locating pins are slotted. In practice, there is usually some 'slack' in this arrangement which means that when a loco starts, it can 'leave its tender behind' until the slack is taken up. This can often be observed as the distance between tender and loco momentarily increasing. In model form, it doesn't look very good and it is usually supplemented with a 'clunk' sound. If the loco's motor vibrates at slow speed, this can cause a repeated clunking sound.
The Heljan 43xx does have this effect to a small degree, however, after practical usage and the fitting of extra weight in the tender, it was found that no further action was necessary at this stage.


Fitting coal in the tender

In recent years, manufacturers have made great strides in making more realistic-looking coal in tenders, however, it can never be better than using real coal:


Here, we have used the traditional watered-down PVA method, with a little washing up liquid mixed in, to fix real coal. When applying PVA, it is always worth while doing so with the body separated from its chassis as you never know where the PVA will run, potentially fixing the body to the chassis such that the two can never be separated again!


Painting the tender wheel rims

Strangely, the locomotive wheel rims are painted, but the tender wheel rims are not. So we paint them:


Painting the pony truck wheel rims

Like the tender wheels, the front pony truck wheel rims are also not painted, so we paint them:


Painting the front pony truck axle

In smaller modelling scales, we can usually get away with not painting front axles because there is usually some kind of coupling pocket/mounting which hides it and it is generally small enough not to be easily seen, however, in 7mm scale, we can't get away with it because we have a prototypical view of the front end, complete with axle in view. We therefore need to paint the axle. Care needs to be taken so not to interfere with the bearings. I applied some 'Vaselene' as a lubrication:


Fitting the AWS equipiment

The AWS equipment is supplied as a separate fitting in the 'bag of bits' in the box. We fit it here:


Remounting the smokebox number plate

The smoke box number plate mountings have obviously been designed for 'durability' however, it looks very crude because it 'looks upwards' due to being mounted to the curvature of the smokebox door. We remove the number plate, file down the stays and re-attach it so that it sits vertically and flush:


Applying light weathering

I model all of my locomotives to look like they are 'used' and to give that appearance, I weather them using my standard 'light weathering' technique:


Related Articles

Review of the Heljan 7mm scale ex-GWR 43xx No. 5306 [4313]
Index of Articles


Graham Plowman (24/01/2020)



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