Engine Specs: What is realistic?


New member
Hello all,

I've been playing around with the test track feature in Trainz 22 to do some experiments, mostly with new and old JR and RRMods content. Throughout my tests, I've noticed a few differences between the engine specs of identical locomotive types and I'm curious which of them are performing the most accurately.

One of the biggest things I've noticed is that the new JR GEVOs and modern EMDs (ACe, ACU, ACC) have a drastic reduction in power curve compared to the old models once their speed increases. For example, if a new JR SD70ACe is traveling at 40mph, notch 4 is required to get any tractive effort at all. Compare this to the older ACe enginespec from JR which provides around 5,500lbf of tractive effort in notch 1 at the same speed. Starting tractive effort for both engine specs, however, is practically identical.

Another interesting comparison is the difference between RRMods and JR engine specs altogether. RRMods models take a while to load tractive effort whereas most JR models load almost instantly. I would assume the RRMods engine specs are more realistic in this regard. However, I think it's important to note that all of the RRMods GEs (AC4400, C44-9, and even the B40-8) use the same engine spec: "GE 4400 AC". This is fairly understandable regarding the Dash 9, but using it for the four axle, lower horsepower Dash 8 seems a bit absurd.

Finally, the new JR AC44C6M produces signifcantly more tractive effort at high speeds compared to the GEVOs; around 10,000lbf at 40mph in notch 3 compared to 0lbf from the GEVOs. Again, starting effort is around the same. This is interesting to me because I would assume they would have very similar performance.

So, I'm ultimately curious which engine specs are most realistic because I'd like to assign the best engine specs to their prototypical models, regardless of their Trainz creator.

Thanks for the help!
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Have a look in Content Manager for the "late" Bill69 engine spec's. I've found most of his steam engine effect's to be reasonably prototypical/realistic...

Cheers, Mac...
Enginespecs are a generally poorly understood part of the locomotive creation process. It's a shame really as there are some really great models/textures around, somewhat let down by their enginespecs.
To be fair, it's not just the enginespecs that have to be correct to get realistic performance in trainz. Each wagon also needs to refer to an accurate enginespec file and to further muddy the waters, each commodity loaded aboard the train also needs an accurate weight configuration.

Given all the variables here and the fact that so many of these spec files are wildly off, getting accurate train performance in trainz is a bit of a struggle.