As far as repaints for Train Simulator go, Stream Lines has been one of the most restrictive payware companies out there. For whatever reason, they chose to ban the distribution of repaints on their models.
This is in stark contrast to Maple Leaf Tracks, which eagerly approved the distribution of repaints of its models, with an eye towards driving up sales of the base product. I have a friend who, while not really caring for modern Canadian National/Canadian Pacific routes, purchased MLT products to get access to the base models which wound up being repainted in NSR, CSXT, or other liveries. He is particularly fond of the SP/NS SD70M model as repainted for the Susquehanna, and regularly complains that a good F45 is not available.
The problem with the SLI policy was twofold: One, in that some people chose to ignore it and distribute repaints on the sly to their friends and two, some folks chose to continually show off their repaints of SLI models as if to say, "Look here what I have, and what you won't". One chap in particular took great pleasure in posting his SD70ACe repaints---such that I often wanted to tell him to knock it off, since he could only be in it for the self-aggrandizing adulation of the MSTS user base.
This all changed with the new year: SLI announced a change effective 01 JAN 2008, specifically allowing the creation and dissemination of repaints. This is a very good move in my opinion; not only does it restore them in my opinion, but it also makes me have a reason to look at their product catalog with renewed interest. (Set aside for the moment that I have no particular use for BN/ATSF/BNSF/UP merchandise.)
For an Eastern railroading fan, the SLI policy shift means that I can have
If you're wondering, NS 2702 and CR 4106 are both EMD SD80MAC locomotives. The NSR currently has 17 of the 30 SD80MACs built on the roster, hauling coal and local traffic in Pennsylvania. CSX Transportation has the other 13 units doing various work on the Eastern end of the system.
I eagerly await the release of additional repaints to the model, and hopefully we'll wind up with all of the CR, NSR, and CSXT fleet in the near future. Want your own SLI SD80MAC? Get it here. If you're looking for the NSR repaints, NS 7202 and 7211 are available from Train-Sim.com as ns807202.zip and ns807211.zip respectively.
I'm told that the best sound configuration to use is the SD90MAC/43 provided with the MLT Rogers Pass route, with a Conrail-specific RS3L. Likewise, the SD90MAC/43 cab is reportedly the preferable arrangement.