Thursday, 1 June 2017

Marbelup Models DB Loco Kit Project


The Marbelup Models project to produce a 3D-printed "kit" of the Westrail DB diesel locomotive in Sn3½* scale is progressing well and the 3D design is complete!  Test prints of all parts have been ordered from i.Materialise in Belgium and should arrive around mid-June 2017.

Completed 3D Design (Computer Rendering)
Basically, the "kit" will consist of 3D-printed parts for loco body, underframe, fuel tank and bogie sideframes,   The general construction will be similar to the Marbelup Models D and DA locos.

The model represents the DB in "as delivered" form.  As is common, some changes were made over the working life of the locos.  The most significant change is to the steps.  The steps at the ends were built out so as to be vertical, rather than inset on the original loco (to clear platforms).  Also the side steps behind the cab, which were originally attached to the front bogie, were replaced with longer steps hanging down from the underframe.

The expected "kit" cost will be about $410 per loco.  This is a bit more than initially estimated, partly due to the fact that the DB is a large loco.  Also, i.Materialise have removed the discount for ordering multiple parts, which adds a bit to the cost of the smaller parts (bogies, fuel tank, etc.). (Actual cost subject to variation due to exchange rate variations against the Euro and/or prices increases in 3D printing.  Current pricing is based on AU$1.00 = 0.666 Euro.)

Note that the majority of the 3D-printed parts will be printed in "Standard Resin" by i.Materialise.  Standard resin is a relatively new material and is translucent with a yellow tint.  The "Prime Gray" material, used for most previous Marbelup Models items, is still available but is about 30% more expensive than previously.  Initial indications are that the print quality of Standard Resin is equal to or better than Prime Gray, and the material specification indicate that it is stronger and less brittle.

To complete the loco, the purchaser must also source a mechanism as well as some detail parts, screws, couplers, DCC decoder (if required), paint, decals, etc.  Assembly instructions will be available online.

There will be two options for the mechanism.  One is the "inline" drive bogies available from Hollywood Foundry, as have been used for the D and DA locos.  One or both bogies can be powered, depending on the modeller's preference.

The second option is to use the motor and drive bogies from a ViTrains UK Class 47 loco.  The Vitrains motor is fitted with flywheels and the assembled mechanism is smooth and quiet.  The drive is to the outer 4 wheels of each bogie, the centre, free-rolling axles being lightly sprung.

See Summary of Mechanism Options for more information.

Marbelup Models has purchased several ViTrains locos from the UK.  These are available for purchase as a "donor" mechanism at a cost of $140 each.  This compares favourably with the Hollywood Foundry mechanisms which cost around $200 for single bogie drive and $250 for double bogie drive (including cost of NorthYard wheels.)

The 3D-printed underframe will be available in two versions, to suit either the ViTrains or Hollywood Foundry mechanism.  The different mechanisms are not interchangeable.  The 3D-printed bogie sideframes are also specific to each mechanism.

The coupler height of the DB loco has been set at the correct scale height for WAGR/Westrail narrow gauge rollingstock, i.e. 12.2 mm (above rail height) rather than the HO coupler height (9.9 mm) which is commonly used for most Sn3½ models.  This has been done because the correct height "looks better" for modern locos and rollingstock.  Provision has been made in the underframe design to lower the couplers to match the HO coupler height by using Kadee #149 couplers which have an "overset" shank together with a spacer approx. 1 mm thick between the coupler box and mounting pad.

Some modellers have paid a $100 deposit as per the initial invite for "expressions of interest" published in May 2016.  Those who have paid a deposit will take priority as the kits become available.  Additional kits will be available after the initial orders have been fulfilled, and there is no fixed limit to the number of kits produced, due to the 3D-printing process which allows additional kits to be produced "on demand".

Deposits are still being accepted, which will secure a place in the "queue" for delivery.  A $100 deposit per loco can be paid by PayPal (to marbelupmodels@iinet.net.au) or Bank Transfer.

Expected delivery time: 1 year, i.e. progressively from end of June, 2017, based on the order in which deposits have been paid.

Deposits refundable only if Marbelup Models unable to deliver, for any reason, 2 years from commencement, that is by end of June 2018..

You can pay the $100 deposit using the PayPal link below:


Specify Scale and Gauge*

Please email Marbelup Models for bank details if you wish to pay by Bank Transfer.

Please note that complete ready to run locos will not be available from Marbelup Models, although it is possible that "third parties" may offer an assembly and/or painting service at additional cost.

* The DB loco kits proposed in HO and HOn3½ scale will not be produced at this stage, due to lack of paid deposits from HO modellers.  The idea of producing kits in HO scale may be revived at some time in the future but only if there is strong interest.