There are two variants included: Unstreamlined
and the infamous 20th Century Limited Dreyfus Hudson
First the good
1. The detail is amazing. When you open the windows, it is reflected outside the loco. You can swing out the wind breaks on the outside of the cab, and that is reflected in the heads out view. The three roof vents open on the top of the cab, as well.
2. The water "dances" in the sight glasses so you have to watch for a couple seconds to get an accurate sight reading.
3. As far as I can tell every valve in the cab works, including the sight glass shutoff and drain valves. The firebox door is able to be anchored open in the F4 HUD, where the only locos I have encountered that in before are the PRR K4 and the Smokebox FEF-3. This is the first loco that I have encountered where the firebox door pedal opens the firebox doors when clicked on. When you release, the doors close.
4. The valve gear reflects on what setting the Johnson bar is in. This is becoming more and more common in TS, but it isn't common enough.
5. There are plenty of steam and particle effects, and the cylinder cocks alternate with the stroke of the piston. Again, becoming more common in TS.
6. The sounds are well done. They aren't too quiet or too loud. The whistle doesn't sound like it's in a loop, a problem with some steamers. Each chuff is very defined when starting a train, and there is a definite "bark" to the exhaust.
Now for the bad, and there isn't much.
1. The boilers are too happy. It is darn near impossible to kill your boiler pressure. The safety valves pop off every 4-5 seconds or so, which leads into
2. The locos use water extremely fast. On a run between Waterton and Riverside on the RW&A donationware route, I used nearly 3000 gallons of water, starting off with a full tender. I kept to the speed limit the entire time, but still found myself adding water every few miles. I don't know if this is a consequence of the extremely happy boiler or not.
3. A minor visual issue is the lack of air hoses on the couplers. Again, a minor issue.
All in all, these are fantastic locomotives that I would happily pay $20-$30 for, and they are freeware. Add in some pre-made consists with rolling stock and these would be top-shelf payware DLC.