Indian Railways operates India's railway system and comes under the purview of the Ministry of Railways of Government of India. Indian Railways operates more than 4000 cargo and goods trains daily.^[1] It hauls variety of cargo to cater to various requirements and have specialized rolling stock corresponding to the cargo hauled. Indian Railways uses a specific wagon numbering system, adopted in 2003.^[2]

Wagons are allocated 11 digit codes for identification.^[2][3] The first two digits indicate the wagon type, the next two digits indicate wagon ownership, the fifth and sixth digits indicate the year of manufacture, the seventh through tenth digits indicate unique wagon number and the last digit is a check digit.

These two digits indicate the type of wagon.^[4][2] There are 243 types of rolling stock used for cargo operations.^[5] These include covered wagons, boxcars, flat wagons, flatbeds, open wagons, hoppers, containers, automobile carriers, defense vehicle carriers and tankers.^[6][7]

Wagon type code

These third and fourth digits indicate the wagon ownership. This might correspond to specific railway zone or other entities.^[2]

These fifth and sixth digits indicate the last two digits of the year of manufacture. For example, a wagon manufactured in 2016 will have a code of 16.^[2]

Seventh to tenth digits indicate a unique four-digit individual wagon number. This is a running serial number from 0001 to 9999 with numbers from 0001 to 0999 indicating wagons used by departments of Indian Railways and numbers 1000 to 9999 are for other traffic.^[2]

The last digit is a check digit, which is calculated using a six-step algorithm as indicated below.^[2][27] Let the first ten digits be represented by C1 to C10 with C1 being the first digit, C2 the second digit and so on.
Step 1 : Starting from the left, add all the characters in the even position. S1 = C2 + C4 + C6 + C8 + C10
Step 2 : Multiply the sum by 3 to get S1 x 3
Step 3 : Starting from the left, add all the Characters in the odd position. S2 = C1 + C3 + C5 + C7 + C9
Step 4 : Add the sum of step 2 to the sum of step 3 to get S4 = S1 x 3 + S2
Step 5 : Round this total up to the next multiple of 10.
Step 6 : The check digit is the number required to the added to round up to the next multiple of 10. If the total is already a multiple of 10, the check digit will be zero.

For example, if the first ten digits are given by 3110169521
Step 1 : S1 = C2 + C4 + C6 + C8 + C10 = 1 + 0 + 6 + 5 + 1 = 13
Step 2 : S1 × 3 = 39
Step 3 : S2 = C1+ C3 + C5 + C7 + C9 = 3 + 1 + 1 + 9 + 2 = 16
Step 4 : S4= S1 × 3 + S2 = 39 + 16 = 55
Step 5 : Next 10th multiple of 55 = 60
Step 6 : Check digit = 60 - 55 = 5
Hence the eleventh digit is assigned as 5 for this particular wagon.