Servicing a Hornby Dublo 3 rail 7037 Swindon Castle locomotive


The Hornby Dublo range of locomotives are very well designed and robust models. However, they are now getting on in life and will need some care and attention as time goes by. The effects of corrosion, dirt, debris, foreign bodies, ware and over (or under) lubrication can have a significant effect on the performance of the locomotive.

In this article we show the steps required to fully service / repair a Hornby Dublo 3 rail 7037 Swindon Castle locomotive. On delivery this locomotive was non functional and when complete it performed as good as new.

Hornby Dublo locomotive as delivered

This is the Hornby Dublo 3 rail 7037 Swindon Castle locomotive as delivered to us by its owner. Everything looks OK from the outside but the locomotive didn't work when initially tested on the bench.

Further diagnostic testing proved that this locomotive would make a full recovery with some simple servicing actions.

Knowing that this locomotive would work well again we set about the full service. The first step is to dismantle the Hornby Dublo locomotive to gain the access required.

Note the motion and wheels are left in place as these can be serviced in position.

Hornby Dublo locomotive dismantled

Hornby Dublo chassis as delivered

This is a closer view of the chassis showing that it is complete and generally functional.

The key problems were; a slightly bent motion rod, corroded and dirty wheels, foreign bodies wrapped around the axles and an accumulation of dried grease and oil.

Nothing a good clean couldn't resolve.

This is the chassis once it has been cleaned and serviced. The pick-up wheels have been polished by using the red abrasive wheel cleaning pad.

A tiny drop of light oil is used on each of the moving joints and pivots.

Hornby Dublo chassis service completed
Hornby Dublo motor dismantled

Next, we turn our attention to the motor for this Hornby Dublo locomotive.

The commutator is cleaned and polished, the end float of the armature is checked and set, the brushes are dressed and all the electrical contacts are polished to bright shiny metal.

A drop of oil is used on the motor bearings and teflon grease applied to the drive gear.

This is the motor fully serviced and re-assembled. To complete the motor the magnet is magnetised in situ in the motor.

Bench testing demonstrated this motor to be in very good health and ready for use again.

Hornby Dublo motor serviced
Hornby Dublo motor fitted to chassis

The serviced motor is fitted to the serviced chassis and statically tested on the bench.

All is well at this stage.

The front bogie is serviced and fitted.

The axles are cleaned and lubricated. The wheels are cleaned also.

Hornby Dublo front bogie fitted
Hornby Dublo chassis fully serviced

This is the Hornby Dublo motorised chassis fully serviced and waiting for the body to be re-fitted.

Before that we service the tender too.

This Castle class Hornby Dublo locomotive uses the tender as the electrical pick-up from the third or central rail. Therefore, in order to complete the service the tender must receive attention too.

The tender is dismantled to allow the necessary components to be cleaned and serviced.

Hornby Dublo tender dismantled
Hornby Dublo tender part cleaned

Here the wheels and axles of the tender have been cleaned.

The front (right of image) central pick-up has been polished while rear rear pick-up has not been cleaned. This shows the original condition of the pick-ups before they were polished.

This is with both the pick-ups polished on the tender.

Hornby Dublo tender fully cleaned
Hornby Dublo tender serviced

When all the electrical contacts are cleaned and polished the tender is reassembled and a small drop of oil added to the axle bearings.

The action of the rear coupling is tested and adjusted as necessary.

Once the motorised chassis is confirmed as working well the body can be refitted and the locomotive is tested again to ensure fitting the body hasn't caused any further concerns.

Clearance and action of the motion in relation to the body is checked too.

Hornby Dublo locomotive serviced
Hornby Dublo locomotive completed

This is the Hornby Dublo 7037 3 rail Swindon Castle locomotive completed. It may look very similar to when it arrived but it now works as good as new.

A simple clean and service can make a massive difference to performance. In this case from non functional to fully operative and with no new parts, just a few tiny drops of oil.




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