Malcolm models the South Australian Railways in N scale and uses 3D modelling to produce models. In the past some of the models were used as masters and released as kits by Aust-N-Rail and Peter Boorman's Workshop. Now that Peter has retired from the N Scale casting scene, many of the models were made available from Shapeways under Malky's N Scale Models at the Shapeways shop: https://www.shapeways.com/shops/malky-s-n-scale-models

Some of the models have now also been made available from alternative sources:

Rob Carpenter's Aust-N-Rail: Aust-N-Rail - HCA cement hopper, 8300 brakevan

and Geoff Biggs' Dogspike N Scale Models: Dogspike N Scale Trains - Redhens, Jumbos, Superchook, Steel cars

These two suppliers use resin printers which can produce a very good surface finish, as well as finer details than previously possible. Their versions of the kits will include some added details such as handrails, steps and similar which previously had to be etched brass. The Shapeways option will remain open for the foreseeable future. 

Instruction sheets for these models are available here:

Redhen 300 class instructions                               Redhen 400 class instructions

Redhen 860 class trailer instructions                      500/600 class Steel Car Instructions

Baby Health Car instructions                                 Poison Train Instructions

W wagon instructions                                           SHBX Grain Hopper Instructions

HCA Cement Hopper Instructions                          D Mail Van Instructions 

Sf Sheepvan Instructions                                      S Bogie Sheepvan Instructions

Joint Stock Sleeper Instructions                            Joint Stock CE Van Instructions

Joint Stock D Mail Van Instructions                        Sleeper Finnis Instructions

Early Series 8300 Instructions                               JCP Instructions

VR X Class instructions                                         Brill 75 Railcar and Trailer Instructions 3D printed Version

SAR Ballast Plough Instructions                             SAR Z Ballast Hopper Instructions

Superchook 2300 Instructions                               Superchook 2500 Trailer Instructions

CGP/AVBY Instructions                                         Bluebird TM-12R Chassis Adapter Instructions

2000 Jumbo Instructions                                      2100 Jumbo Trailer Instructions

2000 Jumbo Chassis Modification Instructions        Brill 55 Railcar Instructions 3D printed version

HO Scale Model Instructions

HO Scale Water Column Instructions

Decals and Custom Etched Brass Parts

Decals and, where applicable, custom etched brass parts are available to complete these models, as well as some extra decals for Peter Boorman's Workshop kits.

A listing is available here: Decal and Etched Parts List