Modifications to improve tight radius performance and coupling distance: Redrill new bolster hole in the underframe as shown. Drill a new coupler mounting hole at the extreme end of the underframe. Install a 1016 coupler in the new hole. Flip the truck around 180 degrees and install in the new bolster hole.
The result: Straight line coupling - Coupling on an 11" R curve (Not pretty but it works. This is absolute minimum radius with the change, before my cars would derail on an 11" test loop)
Tony, why is it necessary to turn the trucks? Would it not be sufficient to move the coupler inwards? Cheers Dirk
Turning the trucks around solves two problems. 1. Moving the bolster pin toward the end of the car shortens the overhang on curves. This minimizes the offset in the ends of the cars when entering a curve. 2. When you move the coupler back, the coupler box is now set in between the truck side frames. Moving the truck pivot closer to the coupler allows for greater swing in the truck. If you move the coupler and not the truck you can get closer coupling but end up with a truck that only swings enough to go around a 16" or so radius. The way the cars are stock, there is more overhang at the ends of the car on a curve than in the middle of the car. This caused problems enter and exiting curves. Once in the curve, the cars worked fine. If you have very gentle easements, the original configuration would have been fine except for the excessive distance between the cars. When you try to get closer coupling, there was no place to drill and mount the 1015 coupler, it would have ended up in the crack between the body and the underframe. Going to the 1016 solves the mounting problem and gives the coupler a longer shank for greater swing so it can handle more offset in the cars.
Tony, Thanks for this illustrated conversion. I have been puzzling about these and had concluded that 1015s were not going to be the answer. Where, for example, would the new hole go? I hadn't answered that, and without filling the existing hole and somehow establishing a place with enough integrity to permit drilling a new hole I hadn't figured it out. An 11" radius is tight enough. I plan on keeping these mostly to 18" radii and wider.
Tony - thanks for starting this most needed thread. I only have one heavyweight so far, but will no doubt accumulate more. The only thing I don't like about them "as delivered" is the coupling distance. Based on your experience, do you think I would need to reverse the trucks and also go to the 1016 if the minimum radius I want to run them on is ~24"? From your photos, it looks like with the 1016's there is still ample space between the diaphragms. Would a 1015 make them butt up against each other? Thanks. Jack
For 24" radius, I doubt you would need to flip the trucks. As far as the coupling distance. you really can't make it any closer. You have to have room for the coupler to work. As they are, when you compress the couplers together, i.e. a backing move, the diaphrams are as close as they can come to touching, with out actually touching. Another project I would like to play with is using American Limited diaphrams on them so that there is some give in the diaphrams. The MT diaphrams are supposed to float but the spring is them is much too stiff to actually let them touch. The American Limiteds are much more forgiving. Now we just have to decide how to make them work with the least amount of effort. It would be really nice if the came up with a kit that would snap in place of the MT parts. (Hint Hint!)
Tony, many thanks for the explanation. I plan to use ALM diaphrams on my cars, so I guess I will need to do some experiments to see if I need to turn the trucks. I was wondering about the way MT has mnounted their diaphrams, never realizing that they are supposed to compress... Cheers Dirk
Here's another thought for you guys: I've taken all my MT heavyweights (about 12 of them) and converted them to MT Z scale #905 couplers. Take the trip pin off the 905, take the stock coupler out, re-use the mounting pin that was there for the factory coupler, insert the Z scale coupler and you're done. It considerably shortens the distance between the two cars and looks better anyways. I have not had any reliablility issues with these on my home layout (19" radius curves....I haven't tried to couple up on a curve, but they don't uncouple going around the layout). If you are trying to run these on an N-trak layout, you may have some issues going over module joints as the coupler are smaller and don't have as much up and down travel. I have not tried this with the AL diaphrams, but I would bet they would look great with the smaller couplers. Give it a try. Nate
Tony, Although, I like what you did and your presentation. I wouldn't flip the truck, leaving well enough alone. The advantages are minimal with regard to tighter radius curves (which so many seem to be infatuated with). As you illustrated...on the 11 1/2" radius curves the over hang is excessive (and they don't look right riding that curve). As far as the distance between the cars. I like Altohorn25's idea. Those Z scale couplers would do the job nicely. Looks like we have a musician on board. Welcome aboard it's good to have you here.
great stuff Tony! I honestly don't get why MT put the bolster towards the center of the car instead towards the ends - it seems to me this would be best all around. Having them towards the center acts to exagerate the overhang on curves. I'll probably move the bolsters out like Tony did. Mark
Fliping the trucks solves clearance issues with the back end of the coupler. If you are operating on less than 16"R curves you just about half to do it. It also eliminates the horible overhang on the ends of the cars. This is most evident when transitioning from straight to curved track. Even going into a 12" radius curve, where one car is on the stright and the other fully on the curve, the stock cars diaphrams are offset their full width apart. Moving the bolster pins closer to the end of the cars cuts that offest in half. Providing less stress on the couplers and it just plain looks better. My home layout will have 14" miniumum so this is important to me to cure. Z scale couplers will exasterbate the problem, unless like Altohorn, you are running on large radius curves. They have a shorter shank, and still mount at the same point. They don't have enough side to side swing to deal with anything but large radius corners. The stock 1015 couplers will derail the cars at the transition from straight to 11" radius. Everything in the conversion was done for a reason. It all works together to make the cars run and look better. I always aim for 11" radius (my Kato test loop) when building things. If it works on 11", it will work even better on larger radius.
I would greatly appreciate seeing a photo of two heavyweights coupled with the Z scale couplers. Thanks! Jack
Tony aka Skipgear, It makes perfect sense and now I have a better understanding. I do operate on 16" radius curves and I understand where you are coming from. I can see the need to flip the trucks. My oversight.
Thanks Nate! That helps a lot. I still might prefer a bit closer coupling, but those Z scale couplers look like they at least bring the distance into an acceptable range.
The smallest that I have to try them on here is 18" and they work fine. I probably wouldn't go much smaller than that. Nate
One more Nate.... Do you have a way of measuring the space between the diaphragms on your Z-coupler-equipped heavyweights? From another thread, it was reported that the unmodified separation between two heavyweights is a whopping .286" (or about 4' prototype). http://www.trainboard.com/grapevine/showpost.php?p=700513&postcount=52 Looking at my MT coupler guide, it looks like a pair of body mount 1027's in lieu of 1015's (is that what MT puts on these?) would reduce the distance by .156, leaving .130" separation (or about 1 3/4' prototype). I'm curious if the z couplers or the 1027's result in a closer separation. Here's the before and the two afters: Nate's Z scale coupler approach: (I hijacked Nate's photo for posting) Tony's photo from original posts: Tony: do you have a way to measure your separation? Thanks to all! Jack
