Well, you’ve already got lots of good answers on operating practices and philosophies, but to answer your first question literally:
Yes. There is no rule to stop you from running a train longer than your longest section of straight track, or, for that matter, as long as all sections of track, whether they be straight or curved. The reasons why you may not wish to do so have been pretty well covered, too.
If you want to run a train like that, there are no rules about doing it or not doing it, save perhaps for those of physics which might make it difficult if you have very tight curves or other restrictions. Otherwise, just do it and enjoy it.
My layout is an around-the-room style, but towns are still unprototypically too close together, and the passing sidings will accommodate trains of only 10 or 12 cars. Occasionally, though, I like to run a long train just for the satisfaction of being able to get it around the entire layout without “incidents”. [swg]
Here’s a sketch of the layout room (don’t have a trackplan, as it was built without one), but I have run a train of over 70 cars completely around the room from Port Ma
As far as train lenght on a 4x8 footer…Seeing I only had two over the years I like my train lenght about 8-10 cars but,I always operated my loop layouts as “out and back” branchline-x many loops between yard and the end of the branch where the industries was located…
“I think a small layout can work well with a long mainline type train that runs through the scene”
I don’t have a “large” layout, though more than a 4x8. I’m 12’ along one wall, 12’ along the next, and another 8’, forming a U if you will. My longest straight section of track (visible) is about 4 1/2 feet long, an also the longest section of level track. I’m currently running an IHC 2-8-0 Mikado with a Rivarrossi 0-8-0 helper, 26 mixed freight cars and a caboose. There is not one spot on the layout where I can see both the loco’s and the caboose at the same time, and though it looks a little silly with half the train going in a tunnel and the other half coming out, it sure looks mighty fine when viewed at different scenes of the layout. For the terrain, a long, slow freight moving through…[:)]
As many have said already, run what looks good to you and enjoy it[;)]. That’s what this is all about!
If the question is will they derail, then it is no problem to have the engine chasing the caboose. I have a good size layout with about a 75 foot main line run, and was challanged to have the engines chasing the caboose, and someone that the cars would stringline the curves near the front of the train. That did not happen, and there were no derailments. Seems to me it was around 70 cars, with about 540 degrees of curves,( it is a big walk in L shape) My train length is limited to the length of the track in the yards, with a caboose. That is around 15 to 20 cars. Longer than that and it does not look right to me.
What it boils down to is however many you feel is right at the time. I do like to run long trains around in circles sometimes, and at other times I enjoy switching industries. They are both fun, and that is what it is all about. Sometimes I let a train run around on the main, and dodge that train with industrial switch job. DCC makes that so much easier, and also the double track main with two double crossovers also contributes to the enjoyment. Just don’t have many adult beverages before operations, as with DCC it makes it really easy to have train wrecks. Fortunatly I have never that.