MSTS - Helpful Facts and Links - Part 14 (EngineVariables for Steam Locomotives by Slipperman12)

MSTS – Helpful Facts and Links – Part 14 - EngineVariables for Steam Locomotives)

Part 14 of HFL has been prepared by Ged aka Slipperman12 and was first posted on UKTS, but is also posted here by kind permission of Ged

The EngineVariables entry in the eng file doesn't receive much attention. It's not surprising, really, because it doesn't have any drastic effects when using normal Player locos. However, if it's required to switch from the original Player loco to another loco, be it Traffic or Loose Consist, it is fundamental that the correct values are entered. If not, the usual result is that the loco will run out of water!

The "Manual for .eng- and .wag-files of the MS Train Simulator 1.0" by Rudolf Richter and Joe Realmuto ( download from here. ) only mentions that item 5 Water Level "is sometimes missing"; this is a very strange thing to say about a string of parameters! If one element is missing from an array, then those following will be in the incorrect position - this applies in any programming language!

It is interesting to note that the Eng_and_wag_file_reference guide in TECHDOCS (supplied on CD1 of MSTS , but not installed) only shows 9 values in this parameter. Also of interest is the fact that default locos SCOTSMAN and 380 have 10 and 9 values respectively!! To complete the picture, PENDENNIS has 10 and ROYALSCOTSCLASS has 9 values.

After much research in the Forums at UKTS and trainsim.com, I found a 31/8/2008 post by Paul (farrmp) on trainsim.com which confirmed that EngineVariables, at least for steam locos, should have 9 values.

From my tests subsequent to discovering this, I've determined that the 'water level' value is not required; if its function was to set the level of water in the boiler, this is accomplished by the 3rd value (water_mass).

The (now) 5th and 6th values are used to set the quantity of water and coal available for Loose Consist or Traffic locos when they are used to replace a Player loco. Player locos use the MaxTenderWaterMass and MaxTenderCoalMass further up the .eng file. I don't know how the values are used by 'real' AI locos, but under 'normal' circumstances, items 5 & 6 will have the same values as MaxTenderWaterMass and MaxTenderCoalMass respectively. This does mean that if an activity requires that the Player replacement loco should have limited water and/or coal, the appropriate values may be entered in items 5 and/or 6, but a revised .eng file will have to be supplied.

The (now) 7th value sets the colour of the smoke, but is used with other parameters within the .eng file, and it's not possible to give a range of values. Two locos I tested had wildly differing ranges, so it's a case of trial and error to determine the value for the required colour of smoke.

The (now) 8th value is a mystery and I've not been able to determine its function; whatever values I've tried have no effect.

The last value, Coal Quality, has an effect on the Steam Gen Rate (as displayed by F5 x 3). Although the documentation states this value should be in the range 0 to 1, higher values are accepted and lead to a ridiculously high steam generation rate! On some locos the Smoke Quantity also has an effect on the Steam Gen rate.

A summary of the above is shown below in tabular form.



The above is based on a post in UKTS during February 2012, which included the above table.

When installing and/or amending all or any part of MSTS it is strongly recommended that you create a back-up copy, because even with the best will in the world mistakes can and will happen. There’s many a “simmer” who can testify to that.