Without confirming 100%, I'm 99% sure that photo was taken in Fort Worth, TX. That is actually not a train, but rather "protection equipment" for both the Heartland Flyer and the Texas Eagle trains that travel through North Texas. In other words, if a loco or passenger car has mechanical issues these are on standby to assist. (and this is a pretty common scenario) It sits parked near the downtown Fort Worth Amtrak station on most days when not needed.
Now, for the true small layout train, look no further than the Heartland Flyer! It runs with engines* on each end so that it does not require a turnaround move on each end of the short journey between Fort Worth and Oklahoma City. (*often one of the "engines" is a NPCU or "Cabbage" ex-F40PH that has no actual prime mover. But sometimes it is just one P42 on each end. AZL approves of this configuration...lol.) Most days it has three passenger cars, but it is not too rare to see it with only two. The equipment is some variety of coaches usually.