Identifying Rail

Railroad rail comes in all types and sizes. The basic design is the same, but there are different weights, which have different loading capabilities. There are also different types of steel and various types of treatment processes. These different types of steel and steel treatment processes all contribute to the strength and durability of the rail. At first it may seem that the best rail would simply be the hardest and strongest, but depending on the conditions which the rail must stand up against, that may not always be ideal. Sometimes, particularly when laid in tight curves, rail needs to be more flexible. It also must be able to expand and contract with temperature changes. In some switches, it needs to be able to withstand being flexed countless times, as it will be moved every time someone lines the switch. Of course, the most important task is that the rail be able to withstand being rolled over millions of times by wheels each carrying many tons.

Since rail comes in many varieties, it is important that there be a way to identify the various types. This is particularly important for Maintenance of Way personnel, who are responsible for track maintenance and repairs. In the United States, basic rail information is stamped on the web, or side, of the rail at least every sixteen feet. The information is standardized, so rail from any manufacturer can be identified easily and in the same format. Since many companies have manufactured rail over the years, this standardization of information is important. The information stamped on the rail is known as the "Rail Brand," and is formatted like this:

115 RE HH VT Nippon 1999 1111111

This is just an example, but let's look at each part.

The first number can be either two or three digits. It identifies the weight of the rail in pounds for each three foot section. Most modern rail weighs at least 115 pounds per three foot section, and in many areas, main line rail can easily exceed 135 pounds per yard.

The second pair of letters is called the section. The section identifies the engineering association that established the design specifications for that particular rail. While the specifications from one engineering association to another would be similar, there are subtle differences and it is important to know what specifications are being used. The most common section in North America is "RE," which is the identification for the American Railway Engineering and Maintenance-of-Way Association, or AREMA.

The second pair of letters, an "HH" in this example, is the grade of the rail. There are numerous grades of rail, divided into two groups. Rail is classified first as either standard grade or premium grade, and each category has about a dozen subcategories. The grade identification can be any number of letters or combination of numbers and letters, but is usually at least two characters. This example would be head hardened rail.

The third pair or letters indicates the method of hydrogen elimination. In the steel making process, any gases that enter the liquid steel can cause voids, cracks, and other potential weaknesses in the final, solidified steel. Hydrogen has been identified as one particularly harmful gas, however steel makers have several methods to cool the liquid steel in such a way that purges it of gases. In this example, the "VT' indicates that this steel was vacuum treated.

Next the manufacturer is identified. Sometimes the entire name of the manufacturer is used, and other times an abbreviation is used. Rail is manufactured all over the world for North America, and each manufacturer has a unique name or abbreviation they stamp on the rail brand. In some cases, a symbol may be used instead of a name or abbreviation. Nippon identifies Nippon Steel, in Japan.

The last bunch of numbers identify when the rail was rolled in the steel mill. The first four numbers identify the year, and the last series of 1's identify the month, by Roman numeral. The example would have been manufactured in July 1999.

In addition to the rail brand, the manufacturer also places other information called the "Rail Stamp," which has specific manufacturing information. The rail stamp is on the opposite side of the rail from the brand, and includes information such as the heat number, position in the cast, and ingot or strand number. Sometimes a strand may be referred to as a "bloom," which is essentially a blank piece of steel which is then heated and rolled into the shape of a rail.

Because the list of all the possibilities for each piece of information is extensive, I will not post them here. I will post them as a page in our "Other Resources" area. Check there within the next day or two if you are curious about a specific identification you have seen recently.