Feb 04 2009
What Does “Code” Mean in Model Railroading?
What Does “Code” Mean in Model Railroading?
“Code” is a way of expressing the height of the model rail used in model railroading. The rail is measured from the bottom (or foot) to the top (or head) when the rail is oriented in an upright position. This is the position that rail is usually oriented for running model trains on. It is also an incomplete way of expressing the physical size of the rail. (It leaves out such dimensions as the rail width, etc.) Even though it may be an incomplete way of decribing the size of the model rail it is still useful to modelers as a general way of describing how big and to some extent how bulky the rail is. This is useful to modelers who want to model lightweight rail for some purposes (such as branch lines) and want to model heavy weight rail (for main lines).
Because model rail is made from various materials (such as aluminum, brass, nickel-silver, and stainless steel) modelers can not use the practice of the prototype to express how heavy the rail is directly in pounds per three foot lengths.
When railroads in the United States started in the early 1830’s they purchased iron rail from Britain. The weight and general size of the rail was about 40 pounds per three foot section. The steam engines of the day got heavier as they grew in power and size. The railroads quickly ordered heavier rail in the same basic shape. It weighed as much as 70 pounds.
Today it is common for rail to weigh 110 to 150 pounds per three foot length.
We define “Code” as an absolute measurement in thousandths of an inch. Therefore, the definition of code 80 rail is 80/1000 inch tall, and the definition of code 55 rail is 55/1000 inch tall. NOTICE There is NO mention of scale or gauge. Code refers to a measurement of the height of a piece of rail. It does not directly apply to either a scale or gauge.
There are many “code” rails for each scale and gauge. The height or code allows for the flange of the wheels on the engine to run without hitting the spikes holding the ties and the rails together. Unfortunately, if the “code” height of the rail is too high it soon looks unrealistic and is out of proportion with the train and engine.
This creates a trade-off between trouble free running trains and scale precision. Fine scale precision rail is certainly possible with railroad cars and engines designed with smaller flanges. The whole operates as a system.
Check with experienced modelers to find out which train equipment and track works best for your purposes. If you want track that is able to take out of scale loads and abuse (such as accidental footsteps in an outdoor railroad) you may want appropriate scale rail, in your favorite gauge,in the highest “code” number that fits your budget. If you are trying to match prototype practices with scale precision, then determine the height of full size rail and divide it by your scale and find out the code (size in thousandths of an inch). Afterwards, check to if your engines and wheel flanges will clear the spikes. Make sure the manufacturer offers compatible switches. Compare several manufacturers for price, availability, and quality.
Have fun!
Trainguy
