12-Wheel drive?

[blwfish]

I agree that 600 feet of mainline run is well past what almost any of us can fit! In fact as near as I can tell, most clubs don't have a 600 foot main line.

I think you'd agree that running a 60-car train (about 32 feet at minimum other than perhaps ore drags) on a mainline run of 90 feet isn't really that practical. One can barely get two trains onto that main, there's a limit of one passing siding, so only one place to have a meet, and except at that one spot the cabeese of the trains are more or less just touching. I guess I did not allow for the possibility of a double track main, but...

If I assume a passing or yard track length of 32 feet, and I want, say, five towns, that's 150 feet by itself. If there's any non-trivial amount of run between the towns - that is, not merely through a scene divider - I assumed 3x as much track.  3x between towns plus x in the towns is 600 feet where x is 150 feet. OK maybe we don't really need the full 3x but surely we want more than the length of the train between passing sidings, right? It strains credibility if the train is visually in two towns at once, or at least it does to me.

Admittedly I had formulated this for my much smaller idea of trains, and perhaps the formula does not scale up so well. Clearly for, say, a shortline sized train of 8 cars (minimum almost 5 feet with motive power?), you're not really an operating road if there is only six feet of track between stations. That's more of a moving display case. A display case is a valid layout too, but it's a different kind of thing. On the other hand, a moving display case doesn't seem to scale up to the notion of a 32 foot long train.

Trains of that size, at least in HO scale, just don't seem to be very practical to me. My impression is that my layout space - roughly 20x 32 with a helix in a completely separate space - is considerably more generous than average, and it's pretty much inconceivable to me to have even the single longest yard track at 32 feet in length. Even if the yard is arranged as a double-ended semi-staging yard, that's still the entire longest dimension that I have, and even then that 60-car train only barely fits. In fact I found it very, very hard to fit in 14-foot passing tracks and only two yard tracks are that long.

Anyway, on the matter of the couplers, I now won't be surprised if I have a coupler failure, although I doubt I will have many on my own layout. I have only allowed for "only" 14-foot sidings, my grades are not all that steep (one at 3.4% at least in theory) and at least for freight trains my road (C&O) essentially never double-headed so even the heaviest freights with helpers get pushers. Only the passenger trains have all the power at the head end. NMRA RP20.1 suggests that my heavyweight passenger cars (nominally 85') should weigh 7 ounces, so that 12-car train weighs over five pounds... Hmm... never thought of it like that. Maybe I will put the Kadees in the passenger cars as they get built from now on...

[jward]

60 cars on a 90 foot loop sounds worse than it actually is. the layout we ran this experiment on was double track, even 3 track in places. it had 4 sets of crossovers between main tracks, 2 yards, and 2 reverse loop branch lines. i agree that on single track you'd have alot of problems. as a normal practice, we'd run trains in the 20-30 car range. they were much more manageable.

[Doneldon]

I agree that 600 feet of mainline run is well past what almost any of us can fit! In fact as near as I can tell, most clubs don't have a 600 foot main line.

blow-

I guess so! Six-hundred feet is just barely less than ten scale miles. I've never seen a mainline that long though I suspect a few -- very few -- club pikes have them.
                                                                                                 -- D

[K487]

Just a quick note on my experience with (HO) long trains (65 to 70 cars each) and couplers.  I may have posted this before, but here goes:

I use KD and sometimes ProtoMax on ALL cars and especially engines.  The plastic couplers that come with many engines started to fail me.  Here's how.  If the rear loco with a plastic coupler was not coupled to the first car's coupler at exactly the same height, when the train was moving the two couplers would tend to slide vertically in different directions (one up and one down.)  I could then literally see the loco's plastic coupler shank bend vertically, and pretty soon I had a train break-in-two.  And my layout is as flat as I can get it.

So, again, ALL my cars and locos get metal couplers - no more break-in-twos.  I imagine this is not an issue on short trains with no grades.

K487

[Desertdweller]

If you have a closed-loop mainline and want to run two trains in opposite directions, you will need two passing tracks close to equal distance from each other.  If you run two trains in the same direction, one passing track will work for overtaking only.

On my model railroad, I handle this problem by using a double-track main line.  Four crossovers link the two main lines.  This gives the option of using one of the mains as a passing track, or to hold trains staged awaiting running on the other main.

It is important to keep the trains to a reasonable length.  On my own passenger-oriented railroad this means ten cars max, more usually eight or nine cars max, with two loco units.  Longer trains exceed my station platform lengths, as well as inviting operational problems.

Les