Are there any drawing available that show the width and other dimensions of various locomotive trucks? The wheel base is frequently shown but not much else.
I wonder how accurate model trucks are. Some models look like they are wearing clown shoes.
Mark
Ask this over on the MR side to get much more information on both parts of this question.
You don't mention whether you're more interested in locomotive trucks than freight or passenger trucks. The latter has extensive 'prototype' documentation in the various Car Builder's Cyclopedias and some of the Research Reports between the '70s and the early 2000s (and probably more by now, except that so much standardization on cheap 3-piece construction up to 315K has been done).
See in particular the threads on finescale wheelset flanges and treads in HO, for which there is a special NMRA RP. Very few modelers appear to be lining up scale brake gear with the treads. This is not surprising when you look at some of the technical details of doing it 'prototypically'.
For EMD locomotive trucks, the lateral spacing of the primary springs is 79.5" for trucks prior to the HTCR, 80" for all HTCR and HTSC standard gauge variants. I increased it on the HTCR to allow for more lateral axle travel at the middle axle.
What you're after is a plan view of a locomotive truck. I did find this one online:
Since you know the gage, you can scale off of the drawing for dimensions.
Ed
Thanks for the replies. Using the 9' wheelbase or Bogies' 79.5" dimension might be a more accurate measurement to scale from. I'm not sure exactly where on the wheel to measure the 4' 81/2' gage.
Overmod,
Model trucks can't have the brake shoes in line with the wheel treads when the shoes are molded on the sideframes using a flat backed mold. Some manufacturers have separate brake beam parts that do line the shoes up with the treads correctly.
mvlandsw Thanks for the replies. Using the 9' wheelbase or Bogies' 79.5" dimension might be a more accurate measurement to scale from. I'm not sure exactly where on the wheel to measure the 4' 81/2' gage.
I recommend where the flange meets the wheel tread.
I will note that you do not appear to be after precision in your measurements, since you use the term "clown shoes".
Overmod, Model trucks can't have the brake shoes in line with the wheel treads when the shoes are molded on the sideframes using a flat backed mold. Some manufacturers have separate brake beam parts that do line the shoes up with the treads correctly. Mark
There's a difference between "flat backed" and "two part". But, as a consumer, why should that be OUR problem?
I don't believe there are brake beams on diesel locomotive trucks. If there are, please demonstrate.
7j43k What you're after is a plan view of a locomotive truck. I did find this one online: Since you know the gage, you can scale off of the drawing for dimensions. Ed
In this drawing top view, the 79.5" dimension is between the centers of the three in-line holes in the top of the spring pockets. Also, the back-to-back spacing on the wheels is 53.375", the wheels are 5.50" wide.
This drawing is taken directly from the EMD assembly drawing 8140660 for the GP swinghanger clasp brake truck but the annotations of components were added by someone else. The "Blomberg" name does not appear in any EMD documents or drawings, that's a railfan creation.
Ed,
I am looking for precise measurements because I want to compare model dimensions to the prototype. The clown shoes image came to mind when looking at some models where the truck sideframes seemed to be wider than they should be. I've also had F unit models on which the truck swing was restricted because the brake cylinders hit the stirrup steps. I think this is caused by the trucks being too wide.
Model trucks in general seem to have excessive space between the face of the wheel and the back of the sideframe. This coupled with the excessive wheel width and excessive sideframe depth make the entire truck too wide.
At least that is my theory. I'm looking for prototype dimensions to test the theory.
The brake beam reference does not apply to locomotives but rather to freight car trucks.
mvlandsw Ed, I am looking for precise measurements because I want to compare model dimensions to the prototype. The clown shoes image came to mind when looking at some models where the truck sideframes seemed to be wider than they should be. I've also had F unit models on which the truck swing was restricted because the brake cylinders hit the stirrup steps. I think this is caused by the trucks being too wide. Model trucks in general seem to have excessive space between the face of the wheel and the back of the sideframe. This coupled with the excessive wheel width and excessive sideframe depth make the entire truck too wide. At least that is my theory. I'm looking for prototype dimensions to test the theory. The brake beam reference does not apply to locomotives but rather to freight car trucks. Mark
Well, as far as the two axle EMD truck goes, you have a drawing, which Dave says is the real EMD drawing and Dave's dimensions to scale it off. Let us know what you find out!
Of course, the sharp model curves are likely to be the cause of brake cylinders fouling on locomotive steps...
Peter
mvlandsw Ed, I am looking for precise measurements because I want to compare model dimensions to the prototype. The clown shoes image came to mind when looking at some models where the truck sideframes seemed to be wider than they should be. I've also had F unit models on which the truck swing was restricted because the brake cylinders hit the stirrup steps. I think this is caused by the trucks being too wide. Mark
Our community is FREE to join. To participate you must either login or register for an account.