Servicing a Hornby Dublo 3 rail EDL7 0-6-2T LMS 6917 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 EDL7 0-6-2T locomotive. On delivery this locomotive was non functional and when complete it performed as good as new.

This is the Hornby Dublo 3 rail EDL7 0-6-2T 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.

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

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

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

The commutator is cleaned and polished, the brushes are replaced with new brushes and the brush springs are cleaned.

Teflon grease is applied to the drive gear.

Next, we turn our attention to the motor magnet and fixings. All the components are cleaned and the magnet strength is tested. This magnet is good and strong.

It is imperative that the magnet is fitted the correct way round. Fitting the poles the wrong way round could seriously affect the magnetic field strength as the steel pole pieces have retained a little magnetic field all of their own. See the red dot on the magnet.

The serviced motor armature is fitted to the serviced chassis. The end float of the armature is checked and set, the brushes and springs are fitted along with the ground side plug.

A small amount of teflon grease is applied to the armature bearings. The magnet components are then fitted to the chassis.

The pick-up shoe is dismantled and each component assessed and cleaned. All corrosion MUST be removed from all these components. Electrical conductivity is the only job this shoe has to perform.

The electrical current is picked up by the spoon shaped slippers, is passed through the main casing to the bolt and along the bolt into the locomotive.

The thin wire spring provides the force to keep the slippers in contact with the third rail and the other pieces are used to keep everything in position.

The is the pick-up shoe re-assembled and ready to fit to the chassis.

These are the electrical components that fit inside the locomotive. The eyelet in the middle of the green wire connects to the top of the bolt from the pick-up shoe.

The brown waxy cylinder is the suppression capacitor and electrically connects across the live and ground side of the locomotive.

The brown rectangular piece (lower right in the picture) is the electrical insulator which keeps the live and ground components insulated.

Once the motor is complete the magnet is magnetised in situ in the motor and chassis.

At this point all the electrical components have been re-fitted to the chassis and can be tested. Initially power is applied across the motor in both directions to ensure the motor is healthy and that there are no short circuits in the locomotive.

Then power is applied to each of the pick up slippers and wheels in turn, again in both directions. This ensures all 4 pick-up wheels are electrically connected to the chassis and both slippers are electrically connected to the motor live side.

All is well at this point with a strong motor and good motion.

The front coupling and rear bogie have been cleaned and serviced. A small drop of oil is applied to the axle bearings.

The action of the couplings is tested and adjusted as necessary.

This is the Hornby Dublo 3 rail EDL7 0-6-2T 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 just a replacement set of motor brushes and a few tiny drops of oil and grease.