My Mogul tender came with a truck mounted coupler. What are the pros and cons of this arrangement. I need to replace the original anyway so which is best for a tender?
73
Bruce in the Peg
Pro: Couplers have a better chance of lining up on curves.
Con: When pushing cars, trucks have a tendency to skew, causing flanges to rub against rails, leading to derailments.
Dave
Just be glad you don't have to press "2" for English.
http://www.youtube.com/watch?v=zQ_ALEdDUB8
http://www.youtube.com/watch?v=6hqFS1GZL4s
http://s73.photobucket.com/user/steemtrayn/media/MovingcoalontheDCM.mp4.html?sort=3&o=27
Funny thing, my two 2-6-0s have body-mounted couplers that might as well be truck mounted. Reason is, both tenders have three rigidly-mounted axles and no swiveling trucks.
If your Mogul has two swivel trucks, I would recommend body mounting.
Chuck (modeling Central Japan in September, 1964)
I think there are prototype examples of couplers being steered by the trucks, but never directly truck mounted. Bachman did something cool by having a body mounted coupled with a steering mount to the truck on passenger cars. My thoughts if your equipment has reasonable weight, a truck mount wont be a hassle, but far better if body mounted, not that many prototype versions anyways, the truck mounting is obvious to running around curves, but never a problem on small cars and body mounts on 18 inch radius. Long cars and passenger cars will tend to have trouble on the sharper curves with body mounts. But easement in curves solves that hassle than the sudden straight to 18 inch curves. Again its circumatance to the needed operation what you do.
In general, body mounted couplers are preferred. Underbody details can be more complete, the car body can be lowered to a prototype height above the trucks (many truck-mounted couplers have the bodies riding high), and as already mentioned, backing with body mounted couplers tends to produce fewer derailments.
However - and this is a biggie - the NMRA Layout Design Special Interest Group (LDSIG) has a rule of thumb that states curves should have a minimum radius of at least 3 times the length of the longest car measured over the couplers. If this rule is followed, body mounted couplers will work well.
If you use sharper curves - many of us do - then at about the minimum radius equal to 2X to 2.5X car length, truck mounted couplers become essential to allow a car to track around a curve while coupled to another car. Train set cars and passenger cars often have truck mounted couplers for precisely this reason.
Mixing body and truck mounted couplers in the same train while backing or going around sharp curves is often more problemmatic than all one type or the other.
just my experiences
Fred W
Body mount couplers are better for backing moves. The thrust on truck mounted couplers while backing tends of twist the truck and then a flange climbs up onto the rail head, and bang, you are on the ground. The prototype uses nothing but body mount couplers.
Truck mounted couplers can help long cars on 18 inch curves. Lionel used truck mount couplers every where. On the other hand, I have body mount #5 Kadee's on 80 foot passenger cars and they stay on the track going round 18" curves. So truck mount isn't always necessary even on extreme conditions.
A Mogul is a fairly small locomotive, and body mount couplers will work well.
David Starr www.newsnorthwoods.blogspot.com
fwright wrote:However - and this is a biggie - the NMRA Layout Design Special Interest Group (LDSIG) has a rule of thumb that states curves should have a minimum radius of at least 3 times the length of the longest car measured over the couplers. If this rule is followed, body mounted couplers will work well.
Uh oh......... Is an HO scale autorack less than 22 inches long?