Wagon weights

Administrator Joined: 23 Mar 2005 Posts: 1749

The NMRA publish an RP for wagon weights, any thoughts on standard weights for German wagons?

Posted: Tue Oct 13, 2009 7:32 pm

It seems that there is a simple correlation between car length and its proper weight. All you have to do is measure the length of the car and then you know what weight it should be.

I made a simple track with a scale that has the proper car weight along its length. You put the car on it and then read what its weight should be.

This track can also be tilted to different angles to see if the proper rolling and stationary characteristics are what they should be.

Posted: Tue Oct 13, 2009 11:28 pm

I forget the exact formula, but it is in ounces per inch. I bought a small digital scale that is used for measuring out medications and it has just the right capacity or range and accuracy.

I'll have to go to my friend's house and look at my track. I'll even take a picture of it so you can see its construction.

I went to Model Railroader and found the following two formulae:

HO scale: 1 plus 1/2 ounce per inch of length

N scale: 1/2 plus .15 ounce per inch of length

Administrator Joined: 23 Mar 2005 Posts: 1749

Roco Ommi51 approx 100mm

Should be 30gms + 60gms = 90gms however it weighs just 45gms. No wonder I have problems trying to shunt.

I think that my wagons will be putting on some weight before Christmas.

Posted: Mon Oct 19, 2009 11:33 am

Good luck with that, Tim. I have a bunch of those and other than using loads to add weight, I don't see much possibility there (how will you model unloaded cars if the weight is in the load?). Even if the whole thing were made of metal, I somehow doubt it would reach 90g.

We have some skeleton log cars at my Canadian prototype club and they are solid pewter, with some substantial cross sections in some places and they still fall about half an ounce short of NMRA weight if they are unloaded. Too bad irridium is $350 an ounce; at twice the density of lead it would make a popular product for adding weight to model trains.

Jurgen

Member Joined: 24 Mar 2005 Posts: 125 Location: Kent, UK

Tim,

NEM 302 suggests a weight of 0.40g/mm for H0 wagons. On this basis, the Roco wagon is about right.

See http://www.morop.org/de/normes/ for the full details.

Could the difference in standards between Europe and the US be due to the differences in wagon and/or coupling design?

Tony

Administrator Joined: 23 Mar 2005 Posts: 1749

Tony,

I think that you are on the right path, the wagons were too free running for successful use of Kadees and I want them to work as well as they look.

Tim

Posted: Mon Oct 19, 2009 10:25 pm

I used to be in N scale back when the Micro Trains line was introduced they found the wheels rolled entirely too well, so they provided a small coil spring to be placed in the journal between the wheel and the truck frame. This provided enough rolling resistance to keep the cars under control.

Jurgen

Member Joined: 24 Oct 2009 Posts: 45 Location: Beverly,MA

Hi all,
That is a heck of a question!Are the NEM's,wrong?Doesn't this have to do with: 1) the loks drawbar pull? and the # of cars,gradients,etc,etc?

Dr D

Administrator Joined: 23 Mar 2005 Posts: 1749

Kevin,

I think the problem with NMRA stock is the need to 'shakehands' and open the Kadee jaws whilst NEM stock merely relies on a slight lift to the locking hook. Therefore the stock really needs some weight.

The NMRA haulage issues should be resolved with extra motive power- multiple working is not the European norm.

My problems are the free-rolling of the Roco wagons which are the very devil to shunt and given the choice of an appropriate amount of 'heft' or external friction, I choose the former.

Posted: Mon Oct 26, 2009 12:38 am

I have just recently received my first N scale fleichmann coaches and found the same thing. They should weigh 29gm but only weigh 16gm! My loco needs a bit of speed to couple or it just pushes the coaches away!

I wonder if a small coil spring (as Jurgen suggested) or extra weight would be easier/more effective?

Administrator Joined: 23 Mar 2005 Posts: 1749

With a respite in the 'flu symptoms, I ventured forth to buy some weights from the local model (flying) aircraft shop.

Made by Irvine they are self-adhesive iron tablets and individually weigh 5gms. Using the newly acquired PO scales, I calculated that six (30gms) would double the weight of most Roco hoppers except the Tdgs that already tip the scales at 80gms.

The result is astounding, the wagons sit beautifully on the track, no more wobble and each coupling/uncoupling is as smooth as silk. The wagons no longer chase the loco or dance away like timid ballerinas.

Am I satisfied? Of course I am because shunting is at the heart of the new layout and now it is fully functioning just by adding some weight.

Thank you to the NMRA

Posted: Sat Oct 31, 2009 10:50 pm

So where did you put the weight in the Ommi's, Tim?

Jurgen

Administrator Joined: 23 Mar 2005 Posts: 1749

There is no way to increase the weight in the Ommi's using weights without major surgery so they will remain as part of the coal traffic on Pottendorf. However for the remaining hopper wagons on the Quarry layout , it is a sinecure.

Fo further info go to Tips n'Tricks

Posted: Sun Nov 01, 2009 1:03 pm

Tim,

Ok so far, the weighting of stock has convinced me, but does it also improve the running sound, between wagon wheel and rail?

Administrator Joined: 23 Mar 2005 Posts: 1749

It produces a soft bass roar with thirty-four axles rumbling around the room, a much lower note than previously heard.

This old Roco hopper tips the scales at a whopping 110g and rolls just like a real wagon.

Tim

Posted: Mon Nov 02, 2009 11:04 am

Tim Hale wrote:

With a respite in the 'flu symptoms, I ventured forth to buy some weights from the local model (flying) aircraft shop.

Made by Irvine they are self-adhesive iron tablets and individually weigh 5gms. Using the newly acquired PO scales, I calculated that six (30gms) would double the weight of most Roco hoppers except the Tdgs that already tip the scales at 80gms.A

If you don't have a RC shop near you similar (if not the same) weights can be obtained from your local tyre fitters.

Posted: Mon Nov 02, 2009 4:31 pm

Brian,

Good tip,

Thank you

Member Joined: 21 Aug 2005 Posts: 388

when weighting cars take into account the load and subsequent wear on the axlepoints on the frames

Member Joined: 13 Sep 2006 Posts: 89 Location: Thornbury

Excuse my lack of knowledge but over a period of time would the extra weight have an effect on the electric motor dives in the loco? eg burn out?

Posted: Wed Nov 04, 2009 11:28 pm

As long as the wheels can turn, the motor should be fine. Motors burn out when they stall and power remains applied. A loco will haul as many cars as it has traction for, and no more. You simply can't pull as many heavy cars upgrade.

Jurgen

Administrator Joined: 23 Mar 2005 Posts: 1749

Quote:

when weighting cars take into account the load and subsequent wear on the axlepoints on the frames

The lack of wobble and reliable coupling far outweighs* the doubts whether extra weight should be added to wagons.

Tim

*sorry