Years ago, I bought a Walthers track scales kit. I got as far as gluing the buildings together and on to the base but no further. Year later, I am trying to finish some of these languishing kits and this one is slap bang in the middle of my port area.
To model it properly, I needed to find some photos and understand how it all worked.
What are track scales?
Every railroad which carries freight that is charged by weight carried needs to understand how much it is carrying to ensure it charges the right amount. Typical commodities that this might include are coal and ore or grain. The easiest way to do this is the weigh the entire car or hopper that the goods are being carried in.
In the yards of these industries, the railroad cars would be weighed on the way in, empty, and on the way out, full.
The track scales themselves are relatively simple: there is a set of scale rails and, of course, a set of scales to weigh the cars. Some weigh continuously and some require each car to stop in turn. These scales are actually fairly large and there is usually a hut to protect these delicate instruments from the weather.
One key feature is that the locomotive does not run over the scale rails. This is achieved in two ways and the kit provides both options:
- Single set of tracks which the locomotive pushes the cars over but doesn’t itself run over
- Double tracks with switches at both ends and the locomotive runs parallel to the scale tracks on a second set of tracks whilst pulling the cars over them.
I’ve decided to model the latter but if space for switches gets tight, I may have to default to the first option.
Scale Test Cars
Scales need to be kept calibrated and tested and to do this, railroads had their own cars which were a known weight. These were used to ensure that the scales were accurate. This is another lovely detail to model and each railroad had their own, which often differed.
Paul Hobbs sent me his powerpoint which has some excellent photos in it: Scale Test Cars. Here’s a couple that are similar to the New Haven one’s that I will need to use:
As a note, operating practice dictated that they were next to the caboose in a freight train as they had no air brakes, only air lines, and there was a 25mph restriction. That’s another great detail to model in your operations.
There’s a great build of one here at George Dutka’s website.
Models
This is an easy thing to model as it doesn’t take much room – just a few inches and a hut. Plus, it can add operational interest as each car has a set weighing period.
My scales are on the run into the coal pier where bulk shipments are received. They’re probably a little close but I don’t have a lot of real estate to play with:
You can even go as far as to install electronic weigh scales:
I don’t have anything on my fascias so I may find a way to do this on an iPad instead. All food for the modelling thought…
Research
I thought it would be interesting to pull together how I found out all the above as I am no expert on track scales. In fact, I’m not sure I’ve ever seen them in the USA in real life.
Researching a prototype is, for me, half the fun of modelling.
Manufacturer’s Instructions:
The first thing I did was check out Walthers’ photos and instructions which are still available online:
These are a great starting point but don’t have any photos.
My first stop for images is always Google image search. That found some interesting links and some great photos:
- http://www.tonopahnevada.com/CentralNevadaMuseum/exhibits.html
- http://www.whippanyrailwaymuseum.net/exhibits/structures/scale-house
- http://thenhrhtanewhavenrailroadforum.yuku.com/topic/7708/New-Haven-RR-scales-locations?page=2#.V8VeSGVnfiZ
- https://imagebase.lib.vt.edu/browse.php?folio_ID=/trans/nss/trac&start_row=71
- http://www.waymarking.com/waymarks/WMD5DA_Arizona_Avenue_Railroad_Scale_House_Bend_Oregon
Library of Congress
My next stop is always the Library of Congress website. This has so many historical photos and plans that it is a real gold mine for research.
Here are two examples of track scale houses from their collection:
Google Maps
For modern buildings I will also use Google Maps.
I managed to find the following images from Google of the Pocatello track scales. The resolution is not good but they do help when planning colours and a scene. As an aside, I love the view of cracked concrete roads from above.
Magazines
The final thing I do is look through magazines for articles. I did cheat a little because I wouldn’t have found the track scales above in Google Maps without the article but it’s all an iterative process.
I found one article in the NMRA Magazine June 2012 which was very helpful in pulling together some of the final details.
Kathy
I found this article to be very nostalgic and interesting. I was a scale technician many years ago. Railroad scales had to be very heavy duty based on the massive weights of the cars. When testing and adjusting the scales it is important that both ends of the scale agree with each other. Also the 4 corners must agree. Adjustments are made with a wrench and a big hammer. The nose, or tip of each lever , is adjustable. A sliding piece provides more or less force to a common lever connecting all components.
In today’s world, the cars are longer and heavier than in other days requiring a longer scale. This is achieved by hooking 2 or more scales together. Each scale is adjusted independently but they all must agree with each other.
The final piece was the weigh bridge or scale arm. It consisted of a single or multiple bars with sliding weights called “poise weights” each one is calibrated to produce an exact balance to the weight on the scale platform when it is positioned at a precise point on the bar.
It is demanded that the weigh beam or scale head be made of non magnetic material. Brass was the most common material used. Being non magnetic, it prevented unscrupulous weigh masters from adding magnets to it giving a false reading.
Total weight was the total of the readings on the bars. It was usually hand written and signed and dated by the weighmaster. Later technology incorporated a mechanical printer incorporated into the main poise weight. It squeezed the weight onto a carbon copy ticket. One part went with the shipment, the other being kept for the railroads records for billing.
The weather effected the scale zero balance. Snow, ice and rain can accumulate on the deck raising the zero balance . This excess weight was compensated by a non calibrated weight usually a screw adjustment that was adjusted periodically as needed to zero the zero balance.
Modern day scales have no levers. They use a device called a Load Cell. They are a solid piece of metal with an electrical device embedded within that produces a given voltage when pressure is applied. These voltages are all connoted to a central device and added together giving a total weight. Advantages of a Load Cell scale are no moving parts to rust, wear out or break. Being an electronic device it is damaged by voltages caused by nearby electric motors, generators and most severe is lightning. Safety devices are added to prevent these costly disasters.
I learned a bit with your article in that the double set of tracks going over the scale..one set for the locomotive which were not attached to the scale and the second set of rails for the cars which were mounted on the scale frame.
Contact me if you need more information
Regards
Jor Farnham
USA
Jor
Thank you so much. You’ve shared some fascinating information! I hadn’t thought about the weather affecting the scales but of course it would. I also hadn’t thought about modern devices and how things have moved on.
Thanks again and please do continue sharing.
Kathy