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4mm Scale Motorising Options

This page is intended to draw your attention to various ways of motorising kits. No way is definitive, each has their pros and cons and you will need to establish the most appropriate way to motorise your kit.   Manufacturers and suppliers mentioned here can be found in our contacts list.

Below the floor ready to run:
"Spud" bogie by Tenshodo or similar.  These Far- Eastern produced small ready to run motor bogies will fit totally below the floor for most installations and only require dummy sideframes and preferably electrical feeds from pickups on another bogie.   However, being designed for HO scale the majority of wheelbase/wheel diameter combinations are not 4mm scale Southern Electric friendly, though the wheels can be fairly easily be replaced by larger diameter versions.  Obviously the small motor involved can only have limited power so one motor bogie per two cars is advised.  The model will also need to be weighted carefully to ensure maximum adhesion.  These motor bogies tend to have plastic/nylon gears which can wear out or strip.  Some modellers have also reported them overheating if subjected to very heavy use - say for all day at an exhibition.  This can be cured by carefully drilling ventilation holes in the outer casing, though lie replacing the wheels, this will invalidate the guarantee.   "Spuds" are available from many suppliers such as Branchlines of Exeter, DC Kits, Roxey Mouldings, etc.

Almost below the floor ready to run:
"Black Beetle".  For most applications this Australian produced ready to run motor bogie tends to require an aperture in the floor but does not intrude into the body too much.  In essence it is a heavier duty version of the "Spud" using   a larger motor and metal gears. However,  one motor bogie per two or three cars plus careful weighting is still advised, as are additional pickups. The Black Beetle is available up to 40 mm wheelbase and various wheel diameters so is very Southern Electric friendly.  Branchlines of Exeter are the UK main agent for Black Beetle but these bogies are available from other suppliers such as DC Kits.

Kit built bogies:
There are several types of etched brass or nickel silver "fold up" bogie mechanisms which use a double shaft can motor driving two axles.  These intrude into the body but are more powerful than the options above. Known bogie kits are the Branchlines of Exeter MB35 and the Southern Pride P300.  Northwest Short Line produce their Flea ll motor bogie which might be adaptable for certain British-type installations.

Central drive mechanisms:
At the cost of taking up most of the interior of the body a powerful drive can be obtained by a double shafted central can motor fitted with flywheels and driving bogies via drive shafts and universal joints.  Suitable motors, flywheels, drive shafts and gears are available from certain suppliers like Branchlines of Exeter, Roxey Mouldings, Mainly Trains and Northwest Short Line.  There is also a new option of products from a British company MSL hobbies. Bogies may have to be scratch-built or adapted from other mechanisms such as MB35 or RTR. Alternatively certain centrally driven RTR locomotives are prime sources of parts - including bogies with gear towers- which can be used. Although compromises with the bogie wheelbase might need to be taken, look for secondhand bargains or special offers on new stock of locomotives like the Bachmann Class 24/5.  One such new locomotive can cost about the same as a single Black Beetle bogie but the mechanism is several times more powerful.

RTR (ready-to-run) bogies:
Although intruding well into the body at one end, and may require compromises with the bogie wheelbase and wheel diameter, ready to run "pancake" motor bogies from Hornby or Lima can be used. These can be bought as spare parts or stripped from second-hand locomotives.  Whilst "pancake" motors may not be the most refined or responsive runners they are cheap, readily available, spares prolific, robust, powerful and will last for years and years.  Increasing the cost, they can be improved or adapted with replacement nearer to scale wheels from Ultrascale (or certain other suppliers) and Lima pancake bogies can be made better runners by use of a Modeltorque replacement armature.  The currently produced Hornby five pole, 34mm wheelbase, 12mm wheel diameter, pancake bogie is an improved runner of the "pancake" type. MSL Hobbies produce variable wheelbase motor bogies.

RTR (ready-to-run) power chassis:
Replica Railways make a Southern Electric friendly "below the windows" power chassis for 64ft (nominal) stock and soon to come 59ft (nominal) stock with 12mm or 14mm diameter wheels. Please read our review on this product.