The MTM1 trk files have no location within them to select an axle model.
The game automatically selects the AXLE.BIN model when it recognizes an MTM1 trk file.
MTM1 trk file
..............................
truckName
Ferrari 312
truckModelBaseName
ferri312.bin
tireModelName
ferwheel.bin
faxle.rtire.static_bpos.x
3.500000
faxle.ltire.static_bpos.x
-3.500000
raxle.rt......................
I tried adding the two axle-model text lines from an MTM2 trk file, with bizarre results:
placing it below the body model in the trk file.....:
truckName
Ferrari 312
truckModelBaseName
ferri312.bin
axleModelName <----------added
axle3.bin
tireModelName
ferwheel.bin
faxle.rtire.static_bpos.x
3.500000
faxle.ltire.static_bpos.x
-3.500000
raxle.rtire.static_bpos.x
3.300000
raxle.ltire.........
this changes the tires to axles, with the rear axle elevated. The car tumbles faster and faster until the game crashes. The stock MTM1 axle is still visible.
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I then tried placing it below the listing for the tire model(s), as it is postioned in the stock mtm2 trk files.....
truckName
Ferrari 312
truckModelBaseName
ferri312.bin
tireModelName
ferwheel.bin
axleModelName <------------------ added
axle3.bin
faxle.rtire.static_bpos.x
3.500000
faxle.ltire.static_bpos.x
-3.500000
raxle.rtire.static_bpos.x
3.300000
raxle.ltire.static_bpos.x
-3.300000
faxle.rtir............
....that experiment also gave me some unusual results, including tumbling, but the default axle.bin model remained
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Finally, I tried placing those 2 lines below the X,Y & Z parameters, but above the scrape points....the car appeared normal, but the AXLE.BIN axles remained....it would appear that you just cannot change the axles when using an MTM1 format TRK file, short of the "podding at the top of the .INI" method I used.
I'll try a few more experiments, but I won't post anything unless I see promising results.