Tweaking ConvertedMSTS Models

The msts to Rail3D model convertor now produces a very good model and (usually) gets sub-components and textures right. However there will always be a few things that need tweaking:


You should add a GAUGE parameter to the model. For a standard gauge model in Millimetric mode the line is

Gauge 1435


You should add a wheelbase parameter to the model. The wheelbase is defined as the length of fixed wheels (ie not bogies). Thus for an 2–6−4 steam loco, the wheelbase is the distance between the first and last of the coupled wheels. For diesels, the wheelbase is the distance between the bogie centres.


You will want the wheels to turn, so identify the correct include in the model and convert it to a wheel statement. You will need to add the wheel parameters (diameter and phase).


Similarly, if you want the bogies to pivot, you need to identify the correct include component and change it to a bogie component. Note that for a bogie to orient correctly in Rail3d you need to add a wheelbase statement to the bogie component.


msts models usually represent a single instance of a loco: in Rail3d we model a class of locos and allow the program to assign apropriate numbers. It is best to add a suitable number statement to the model file (and easy to do). Ideally the model textures need to be modifed to remove a fixed number (if present) and instead suitable Rail3d number panels added to the model to display the (varying) loco number.


Similarly, where a class of model has names, these can be added to the model file and added to the model with name panels.


For diesel locos you need to add cab terms to the model to set the cab view camera position.

For steam locos the footplate command is preferred and this will allow the user to move the camera around the footplate.

Further on, msts cabs are usually not very good in Rail3D (because msts uses a different view for cabs with a bitmap background etc and Rail3D uses the same model) so you may want to detail the cab and/or add operatable controls.

Tender steam loco’s

As well as the footplate definition for steam locos there are some more tweaks worth adding to tender loco’s

Loco / Tender

Add the keyword LOCO to the loco and TENDER to the tender. This is useful as it allows routing statements in points (etc) to route loco’s (for example to a turntable if a loco needs turning).

Combination model defintions

After conversion you will have a model for the loco and for the tender. It is useful to create a model for the combined pair, such as

Name B1
Unit !B1Loco&!B1Tender

This allows the user to drop the combined loco+tender as one, instead of having to drop each bit seperatly, also, it causes Rail3D to treat the two as one when counting vehicles, so uncouple at 1 will uncouple the loco and tender instead of uncoupling the loco from the tender.

Steam loco parameters

Rail3D and msts treat steam loco physics differntly, so while the convertor makes a reasonable attempt to convert the parameters, you will need to check and tweak them.

Driver diameter

The convertor will produce multiple DriverDia statements, you should delete the unnecessary ones.

Chimney and SafetyValve positions

The latest version of the convertor is better at this, but it’s worth checking the position.

CylStroke and CylDia

Check these, they are usully right.


This normally needs changing as msts and Rail3D treat it differently. It should be specified in cubic metres and is the total external volume of the boiler. Ie it does not differentiate between the water in the boiler and the volume taken by the tubes etc. To get the boiler volume simply multiply the boiler (external) diameter by 3.141 by the boiler length (just the boiler, not the boiler+firebox). If you don’t change it, you’ll probably find the loco running out of steam very quickly.


This needs to be added in square metres, if the value is not available, you can get a reasonable estimate by measuring the firebox length and width from a drawing and multiplying them together. This effects how fast the loco generates steam.


You should add a superheat parameter if the loco is superheated.

Sign your model.

You should use the “sign model” function within the Rail3D editor to mark the model as your work.

See also Steam Locomotive Valve Gear