Posted By Dougald on 04/03/2008 4:40 PM
OVGRS members experienced the same derailing problems with the six wheel trucks on these heavyweights and as a result the cars were seldom run. After widening all the mainline curves to 5 foot radius (10 foot diameter) a few years ago, we took another run at them. Changing over to 4 wheel trucks does not capture the prototypical look of heavyweights which almost always had six wheeled Commonwealth trucks on cars longer than 60 feet. after some experimentation (note that we use only body mounted kadee couplers), it was determined that the weight of the car combined with the offset bolster were primary culprits in causing derailments on the slightest trackage imperfections. This effect is enhanced with sharp curves - and I would call a 5 foot radius curve pretty sharp. We now have cars that have the bolster placed correctly on the cars and centred on the truck. The car is far better balanced and much less prone to derailing, though in fairness, long cars, sharp curves and body mounted couplers do not mix well. Essentially it comes down to a simple point. Passenger cars are big all the more so if they are scale length. If you want heavyweight cars that look realistic then they need to have scale proportions ... they also need to be close coupled with working diaphragms ... and they need proper Commonwealth 6 wheel trucks. For these cars to run reliably, I would recommend larger curves than what many folks use. Think about it for a moment - in HO, a scale length heavyweight is normally thought to need at least 30 inch radius for minimal operation and 36 inch is standard for reliable operation; larger curves are needed for great appearance. HO is exactly 1/3 the linear dims of 1:29 scale. That suggests a 9 foot radius as the minimum for acceptable performance and operation. Since most large scalers rarely "operate" their equipment (in the sense of the small scale crowd) but mostly run their trains to look at, they should imho therefore look the part. Let's get those bolsters centred properly, 6 wheel trucks on those heavyweights and wider curves for better appearance. Regards ... Doug
Excellent, highly informative post that is directly relevant to my upcoming projects.
Does anyone have a suggestion as to where to obtain working diaphragms?
Also, could you elaborate on properly centering the bolsters. I must have missed something there in the context.
OVGRS members experienced the same derailing problems with the six wheel trucks on these heavyweights and as a result the cars were seldom run. After widening all the mainline curves to 5 foot radius (10 foot diameter) a few years ago, we took another run at them. Changing over to 4 wheel trucks does not capture the prototypical look of heavyweights which almost always had six wheeled Commonwealth trucks on cars longer than 60 feet. after some experimentation (note that we use only body mounted kadee couplers), it was determined that the weight of the car combined with the offset bolster were primary culprits in causing derailments on the slightest trackage imperfections. This effect is enhanced with sharp curves - and I would call a 5 foot radius curve pretty sharp. We now have cars that have the bolster placed correctly on the cars and centred on the truck. The car is far better balanced and much less prone to derailing, though in fairness, long cars, sharp curves and body mounted couplers do not mix well. Essentially it comes down to a simple point. Passenger cars are big all the more so if they are scale length. If you want heavyweight cars that look realistic then they need to have scale proportions ... they also need to be close coupled with working diaphragms ... and they need proper Commonwealth 6 wheel trucks. For these cars to run reliably, I would recommend larger curves than what many folks use. Think about it for a moment - in HO, a scale length heavyweight is normally thought to need at least 30 inch radius for minimal operation and 36 inch is standard for reliable operation; larger curves are needed for great appearance. HO is exactly 1/3 the linear dims of 1:29 scale. That suggests a 9 foot radius as the minimum for acceptable performance and operation. Since most large scalers rarely "operate" their equipment (in the sense of the small scale crowd) but mostly run their trains to look at, they should imho therefore look the part. Let's get those bolsters centred properly, 6 wheel trucks on those heavyweights and wider curves for better appearance. Regards ... Doug
Excellent, highly informative post that is directly relevant to my upcoming projects.
Does anyone have a suggestion as to where to obtain working diaphragms?
Also, could you elaborate on properly centering the bolsters. I must have missed something there in the context.
