Bachmann 4MT v Hornby Dublo 4MT

The rail test of the Bachmann 4MT Tank Loco is complete. How does it compare with the Hornby Dublo version?

All will be revealed if you click here

There is more information about the prototype available at the following sites:-

Southern E-Group

Nicks Pix

The Bachmann website does not contain a service sheet for this model.

Happy modelling
Gary

You are right!

QUOTE "Adjustable Magnet Shunt" improves running at slow speeds according to Dublo sales literature.

The Hornby Company general information book records QUOTE that the magnetic shunt was provided for the purpose of varying within presecribed limits the flux available across the field pole tips. It will be fairly obvious that when the shunt is fully engaged a portion of the field flux is bypassed thus weakening the field strength in the air gaps between the armature and the field poles. Thus a very fine adjustment is provided which will enable the field and armature fluxes to be balanced at starting ie when the armature torque is at its lowest to give a smooth start. The secondary effect is that with a weakened field the armature current is increased, which increases the voltage drop across the armature when the motor runs slower. Withdrawing the shunt from the magnet of course has the opposoite effect and the motor runs faster for a given voltage. Normally the strength of the field flux due to the magnet is more than actually required to produce optimum useful power (the point where any increase in power is wasted due to the limit of track adhesion). The shunt does not therefore greatly effect top speeds of the locomotive.

At a Hornby product meeting on 29th December 1961 it was decided to delete the magnetic shunt unit to save on production costs. This was not put into effect until 1963 due to the high stock position. It was the February 1963 edition of Meccano Magazine where the announcement was made that the shunt was to be discontinued. However, due to the high stock position of bodies every 4MT body has a hole in the back, whether it has a shunt fitted or not.

I guess that the stiff competition from Triang forced this cost cutting excercise by Hornby. Too little too late. Wrenn bodies do not have the hole and Wrenn did a very good job with the mold alteration as there is no sign of it at all.

Of course all the effects of the shunt are provided for by the modern control units of today so it is not really required within todays motors.

Happy modelling
Gary

That was the initial batch of 100,000 for the first year!

The thing is look at the Hornby Dublo catalogue for 1955. You have a choice of 6 locomotives! And Triang offered about 10! And these did not change from year to year. Just new items added. The Dublo Class 4MT of 1953 had exactly the same loco number in 1963.

Now the Hornby catalogue of 2005 offers you a choice of over 120 locomotives and the Bachmann catalogue 80 odd. Thats over 200 scale OO locomotives to choose from in just one year!

And then you have N gauge that simply was not around in Hornby Dublo's day.

So you can see that it is really impossible to make a fair comparison as we live in different times.

The only thing for sure is that games consoles did not exist for young boys to play with in 1955.

Happy modelling
Gary