Home   |  Products   |  Workshop Preview   |  View Cart  |  Checkout    |  Contact us  |  News! |   Free Downloads! 

 About Us |  BullAnt Resellers |  GalleryFAQ'sFascinatin' Stuff


The BullAnt Multi-Gauge Motor Bogie

The BullAnt has been developed in consultation with Steam Era Models, the makers of the famous Black Beetle. The BullAnt is not designed to compete with the Black Beetle, but rather complement it. Where the Black Beetle is very effective in gauges of 16.5mm and over, it's design does not allow for gauges narrower than 16.5mm.

This is where the BullAnt comes in, able to cope with gauges down to 9mm. Quite small wheelbases can also be offered, and uniquely, more than 2 axles. There is no fixed wheelbase for a BullAnt, you can pretty much choose whatever size suits.

The BullAnt show below is about the smallest we can do with all features on board. Just to put that little BullAnt into perspective, it is only just a tad over 1 inch in length!

How To Order A BullAnt

The BullAnt has so many choices now in the options available that some of our customers have asked for a little help in explaining how to go about ordering a BullAnt.

So to help explain what the options are about, have a look at our How To Order A BullAnt Page.

The range of BullAnt configurations is too large to show, but the examples shown demonstrate the ability to go from the very small 15.5 mmm wheelbase, to the very large 45mm wheelbase at the rear. Gauges demonstrated are 9mm, 10.5mm, 12mm & 16.5mm with wheel sizes from 8mm up to 11.6mm.

The three axle BullAnt show below has 20mm + 20mm axle spacing, 11.6mm disc wheels, 16.5mm (HO) Gauge and is fitted with the optional more powerful Mashima 1024 motor. Pickups fitted to all wheels in multi-axle configurations. Although this model has equal axle spacing, there is no reason why the spacing between axles cannot be different.

The BullAnt dummy bogie is simply missing the motor and gear components. It comes supplied with pickups to extend the power collection to the dummy. We must point out however, that these dummy units are not particularly free-rolling due to the brass wheel bearings and pickups adding to the rolling resistance. It is definitely recommended to place sufficient weight on the dummy end to obtain best performance.



A brass spine section carries all of the components in a strong, rigid structure. A nickel-silver gearbox frame mounts the Mashima MHK-1015 motor and flywheel, along with 2 brass and one Delrin helical cut spur gears, to transmit power down to just above axle level. Then a silver-steel horizontal lay-shaft runs underneath the brass spine, carrying the steel worms that provide power to the wheels. The gear ratio of 15:1 provides a good balance of power and speed range.

Moulded Delrin gearbox enclosures place the axles in correct mesh with the worms and align the axles across the assembly. Although Delrin is an excellent bearing material in itself, each axle has two brass bearings, one either side of the brass worm gear, to provide excellent wheel alignment and smooth running. Two phosphor bronze thrust washers inside the gearbox enclosures take care of thrust loads along the layshaft.

A Polystyrene plastic sideframe mount has three fingers on each side that can be trimmed off to provide mounting for bogie sideframes at 13.3, 16.5 and 21mm inside spacing. The sideframe mount also carries two phosphor-bronze pickups, making contact with the inside flanges of all wheels. The wheels are solid nickel-silver, to RP25 standard, code 88.

A nickel-silver bolster, attached above the sideframe mount, runs in a Delrin turntable to provide a swivel mounting for the BullAnt to the model. A printed circuit board attached to the rear of the motor features an interference suppression network to make the BullAnt CE compliant.


A great deal of care has been taken with the design of the BullAnt to guarantee quiet, reliable running combined with low maintenance. The prototype BullAnt was run for 650 hours, 24 hours a day to identify wear points. During that time, it travelled over 370 actual miles, or 590 kilometres.

Shortly after we started production, the moulded Delrin spur gears were found to be unsatisafctory, so we had specially cut gears made in a mixture of brass and Delrin with a helical tooth form to improve smoothness and further reduce gear noise. At the same time, we took the opportunity to add two bearings to the idler gear as we had noticed wear in this area with the test unit.

If the Mashima 1015 motor is a tad small for your application, and you need a little more power, the larger 1020 and 1024 variants can be supplied to order. The 1020, while providing more power, also runs slightly slower than the standard 1015 motor, while the 1024 runs faster.

More Ratios?

Shortly after introduction, the BullAnt will be available with a choice of 3 gear reduction ratios. The standard ratio of 15:1 is best suited to larger scale narrow gauge EMU/DMU applications, while optional ratios of 31:1 and 60:1 will be offered to provide better slow speed performance.

More Axles?

An exclusive feature of the BullAnt design is that it provides for 3 or even 4 axles. And the axle spacing does not have to be equal either, you will be able to individually specify the spacing for each axle in the assembly. Even with 4 axles, you can still have power pickup from all wheels too.

However, a word of caution, the BullAnt design provides a rigid wheelbase, there is no lateral movement on the centre axles. This can be a problem with 3 axle configurations where the axle spacing is large and/or small radius curves are employed. A rigid frame of any length can de-rail on corners and sharp points. It is not really possible to advise a minimum radius that the BullAnt will handle as it is totally variable according to wheelbase, wheel size and wheel profile.

We do offer, on the other hand, an option that provides a lateral action on the center axle. With this method, the center wheels have a slightly narrower back to back measurement and employ a nickel silver wheel housing and thinned down wheel bearings. The worm gear is also slightly thinned as well and this combination means that there is 1.3mm of lateral movement on the center axle only. Because of the additional time taken in the assembly of this option, there is a price premium charged.

Really Short & Extra Long Wheelbases?

With a minimum wheelbase of 17mm and a maximum in excess of 60mm, the BullAnt will provide a much needed power source for trams, multiple unit railcars, small industrial tractors and the like. If you are prepared to delete the pickups, sideframe mount and bolster, the BullAnt can be supplied with a tiny 11.5mm wheelbase!

How big is the BullAnt, will it fit my model?

View the Spec Sheet in PDF format, showing typical BullAnt dimensions: Spec Sheet

To save it, right click on the link and choose 'Save Target as....'

Ordering Options?

  • Wheelbase: From 11.5mm upwards in increments of 0.25mm. 17mm upwards can be fitted with pickups and bolster.
  • Gauges: 16.5mm (HO) - 14.2mm (British 3mm Fine Scale - 12mm (HOm or HOn3 1/2) - 10.5mm (HOn3) - 9mm (HOe or HOn30")
  • Wheels: All disc - 11.6, 10.5, 9.6 & 8mm (other wheel types will be added in the future)
  • Motors: Standard, MHK1015 - Optional, MHK1020 or MHK1024
  • Matching dummy BullAnt (non-powered)


A two axle BullAnt will retail at $85.00, and a dummy at $25.00 in Australian Dollars. There will be small extra charges for additional axles or other motor combinations.

How Quickly Can I Get a BullAnt?

We have invested in specialised CNC machinery to make the assembly of the BullAnt as quick as possible. All orders go into a queue and are processed in sequence. We aim to have a maximum of 7 working days from receipt of order to despatch of that order. In any event, provided we can contact you, we will advise you when your order is to be shipped.

Note about Dummy BullAnt

Please note that the dummy BullAnt has exactly the same construction as the powered BullAnt, including brass wheel bearings and these, along with the power pickups that are fitted, mean that the dummy is not particularly free-rolling. These features add a certain amount of friction to the axle, and this is un-avoidable.

About Running In

A number of customers have noticed that their BullAnt is a bit jerky in its movement when they receive it. The motor can also run a bit warm as well. This is an indication that the BullAnt needs to be run in.

Although every BullAnt is tested and run before shipping, we strongly recommend that you run it in when you receive it. Some manufactuers build their mechanisms with loose tolerances in the bearings, usually referred to as 'slop'. We do not do this, all our bearings are made to close tolerances and need to bed themselves in to provide optimum performance. Unfortunately we cannot afford the time to do this with each BullAnt at the factory, or it would increase the cost, so we ask you to do this yourselves.

Hobby Shops, Distributors & Manufacturers?

Retail hobby shops and distributors are welcome. Manufacturers looking for powertrain solutions for their models are most welcome.

Please contact us at sales@hollywoodfoundry.com or telephone us on (03) 5629 1100, International +61 3 5629 1100. Wholesale and dealer prices can be provided to legitimate businesses.

Hollywood Foundry - Copyright 1999-2004 Seamist Pty. Ltd..  All rights reserved.