Ntrak standards dictate that track at the end of a module be set back 2 1/2 inches to allow use of a standard Atlas sectional track to use as a bridge between modules. Now that may be fine for normal modules but in a 12 track three module yard it becomes sort of nightmarish with 24 bridge tracks. I was thinking of joining the three modules together, laying track across the joint and then when all was done using a dremel tool to cut the track at the joint. Also drilling holes in the end frame for bolts to line up the modules when assembled. My other idea was to keep the Ntrak setback at the module ends and make a single multi track bridge unit that would be placed over the joint instead of individual bridge tracks. I like the first idea better as it would be far simpler for set up and tear down and not require rail joiners to be placed nor would it require that power be routed to the bridge track. As long as alignment can be maintained it would be preferable. Has anyone had experience with this and how difficult is it to maintain alignment especially on modules that will see a lot of setting up and teardown such as at shows.
I'm not into Ntrak, but it seems to me that the 2-1/2" setback/bridge track thing is to allow one module to be easily joined to any other module. In your case, the modules are to be joined (at least on the ends with the 12 track joints) only to each other. Or, to look at it another way, you don't have 3 modules, you only have a single module that comes apart into three pieces.
Bill's pretty much right on, as long as the two ends that will connect with other modules use the standard Ntrak spacing, you're fine. I am actually currently building an Ntrak yard based on a prototype yard. I decided to make each track bridged, but once I got off of the 3 Ntrak tracks, the joints are not at the 2.5" setback, but where it was convenient for me.
Do the non-standard interface with the middle section of your yard. That is what we did with our 8 track yard. After you get all your track put down make end protectors for the ends of the tracks on each module. This will keep the ends of the rail from getting snagged on things and pulling the rail up and off of the ties. After you have to relay about 4-5 pieces of rail you will see what I mean. You might want to make it so that you can put your yard up without the middle section. Sometimes you don't need or want a full size yard. While we are on the subject of big yards make sure that you have good power feed into the yard. Don't depend on switch points and rail joiners for passing power into the yard. Put track feeders into the rails. The KENTUCKIANA SOCIETY OF N-SCALERS (KSONS) have two big yards that we use, one is 3 sections of 4ft modules, and the other is 3 sections of 6ft modules. The 6ft sections are DCC wired and controlled. You don't want to know what we have invested in the big yard! We made it possible to put up each yard without the middle section inserted. One other thing I will pass on is to remember that you are going to have to more the yards if you use them with NTRAK layouts. So it is wise to make the modules stackable or such for transport. Having to carry a 3 part yard a city block or so to get to an exhibition hall can get old real quick.
If you really want accurate alignment between modules, call a Tool & Die Supply company in the nearest large city, and buy Jig Pin sets. Jig pins and their socket are precision tool steel, made to align parts of assembly jigs used in many manufacturing industries. You mount a piece of flat aluminum plate 3/16" or more thick to each end of your module that mates to another, (like for the yard tracks). Have a machine shop drill and ream all the mounting holes at one setting by stacking the plates, to insure exact alignment. You will want two pins in one end, and two sockets in the other end. Once mounted, none are removable. Then have them thread four holes in each plate for 1/4-20 or 5/16-18 threads to mount the plates to the end of your module with. Locate these holes away from legs and braces, so you can reach the cap screws to tighten them with flat washers under each head, when the modules are aligned. Then separate the modules and drill and mount two dowels through the aluminum plates and through the wood end piece of the modules to hold the plate in final location. Number each plate to match the mating plate on the other module. Jig pins are made in several fits: For tooling, the clearence is only .0002", for assembly jig sections, it is .0010", for Painting and Sand Blasting Masks, it is .005" The last one would only allow your rails to move .0025" out of dead center in any one direction, and would slide together and apart rather easily. You will want to file a slight taper on the inside ends of each rail to prevent having a sharp corner that "could" snag a wheel flange. (Murphy's Law!) Mount the plate to number one module first, then match BOTH the other two modules to it. This will then allow you to match and interchange modules as required, and all rails will align. Adjust the first module compass level (360 degrees), then adjust the second module's leveling legs keeping it compass level as you raise or lower it to match the first until it will slide in mesh easily by hand. Keep the jig pins and sockets waxed to prevent rust. (Do not oil them! Why? Oil floats on water, wax floats water. Wax is also an excellent lubricator.) When finished, all modules will be matched, aligned perfectly, and level with whatever floor they are on. Email me if you have questions. You will wonder how you ever got along without Jig Pins before. [ 07. September 2002, 05:41: Message edited by: watash ]
Shucks, we did it the hard way with our (KSONS) modules. We clamped them together, drilled holes thru the end pieces, and use bolts to hold the modules together.
As long as the ends that connect to other people's modules are standard, you can do whatever you want in the middle module(s). We have members who have their own connector tracks for their inner connections. We have modules where the tracks are matched together when being clamped, although I do not recommend that process. In fact, we are in the middle of replacing those type of (non)-connections as we upgrade the modules.
How about trying this as an inexpensive and positive alignment connection? Clamp modules together and drill thru an appropriate size hole for a 5/16" or 3/8" T-nut on each side. Mount T nuts to each side and fasten together with hex head all thread bolts. The threads will help hold the alignment without slop and also perform the connection between modules. This would eliminate any hole enlargement if you only drilled and fastened.
The Greenville SC NTRAK club used Atlas rerailer sections glued 3-up on styrene sheet. Drop in the sheet, slide the rail joiners into place and voila. For splicing yard sections you could use whatever number of tracks per splice plate that works out the best. One way not to do it -- another NTRAK club had a 20 foot long yard made up of two 10 foot sections, with all tracks laid up to the very end of the module joint. Now imagine trying to connect all umpteen yard tracks with just half a rail joiner to work with on each side of the module joint eNjoy
