Japan Railways locomotive numbering and classification

This page explains the numbering and classification schemes for locomotives employed by the Japanese Government Railways, the Japanese National Railways and the Japan Railways Group.

Steam locomotives

Pre-nationalization

Prior to the nationalization of Japanese railways in 1906 and 1907, the government-run railways had numbered their steam locomotives only with serial numbers without consideration of the types of the locomotives. From the beginning of the Kobe–Osaka railway in 1874, they allocated odd numbers to locomotives in Tokyo area and even numbers to locomotives in Kobe area, but this was not maintained after the completion of railway between Tokyo and Kobe in 1889. Later, some locomotives, such as Classes A8 and B6 and rack railway locomotives, were renumbered to make groups for easy recognition of classes.

Classes were introduced by Francis H. Trevithick (1850–1931), a grandson of Richard Trevithick employed by the government of Japan for supervision of rolling stock management. He classified the locomotives with one Latin letter (A through Z), which was then expanded to use two letters (AB, AC, AD, and so on).

Later, this simple method was revised to use one letter and one or two digit numerals with consideration of locomotive types. The meanings of the letters were as follows:

*A – Tank locomotives with two driving axles (A1–A10)
*B – Tank locomotives with three driving axles (B1–B7)
*C – Tank locomotives for rack railway (C1–C3)
*D – Tender locomotives with two driving axles (D1–D12)
*E – Tender locomotives with three driving axles (E1–E7)
*F – Tender locomotives with four driving axles (F1–F2)

1909 rule

Following the railway nationalization, in 1909, the railway authority adopted a new system where locomotives were numbered and classified by four-digit numerals. All existing locomotives were reclassified. Numbers 1 through 4999 were allocated for tank locomotives and 5000 through 9999 were allocated for tender locomotives. Here the classes and the numbers acquired a distinct relationship. Locomotives were grouped in numbers and the classes were represented by the earliest number of the group.

*1–999 – Tank locomotives with two driving axles
*1000–3999 – Tank locomotives with three driving axles (3900 and after for rack railway)
*4000–4999 – Tank locomotives with four driving axles
*5000–6999 – Tender locomotives with two driving axles
*7000–8999 – Tender locomotives with three driving axles
*9000–9999 – Tender locomotives with four and over driving axles

Numbers within a class were serial in principle. When the number overflowed (as in Classes 8620, 9600 and 9900), one digit was added to precede the four digits to make the numbers five digit. Class 18900 (later reclassified as Class C51) was exceptionally five digit from the beginning.

This numbering and classification rule survived the revision in 1928. Non-standard locomotives that joined the national railways by means of purchase of railway companies were numbered in accordance with this rule even after 1928. Locomotives numbered and classified under this rule includes the locomotives used until very last days of JNR steam locomotives in 1970s.

1928 rule

Because the 1909 method were going to overflow, a new rule of numbering and classification came into effect on October 1, 1928. Except for Classes 18900, 8200 and 9900 being reclassified as C51, C52 and D50 respectively, existing locomotives were not reclassified or renumbered. After this revision, steam locomotives are classified and numbered with a Latin letter and numerals.

; Example: D51 200

; E:All classes of electric locomotives begin with the letter "E" for "electric".

; Number of driving axles:A letter indicates the number of driving axles. Unpowered axles are disregarded.

:* 2 axles – B:* 3 axles – C:* 4 axles – D:* 6 axles – F:* 8 axles – H

; Class:Together with the letter "E" and the letter representing the number of driving axles, a two-digit numeral following the letters indicates a class. Originally, the number distinguished the three types of locomotives.:* 10–39 - Locomotives with maximum speed 85 km/h or less:* 40–49 - Locomotives for rack railway:* 50–99 - Locomotives with maximum speed exceeding 85 km/h

:As a result of a revision, as of 1987, the rule was as follows.:* 10–29 - DC locomotives with maximum speed 85 km/h or less:* 30–39 - AC/DC locomotives with maximum speed 85 km/h or less:* 40–49 - AC locomotives with maximum speed 85 km/h or less:* 50–69 - DC locomotives with maximum speed exceeding 85 km/h:* 70–79 - AC locomotives with maximum speed exceeding 85 km/h:* 80–89 - AC/DC locomotives with maximum speed exceeding 85 km/h:* 90–99 - prototypes

; Running number: In principle, running numbers begin with 1. However, numbers may be skipped to create subclasses, such as Class EF65 1000 series or Class ED75 700 series.

According to this numbering method, EF81 95 means locomotive number 95 of Class EF81, which is a class of AC/DC locomotive with six driving axles and maximum speed exceeding 85 km/h.

JR Freight

Out of seven Japan Railways Group (JR Group) companies established in 1987, only Japan Freight Railway Company (JR Freight) has built new electric locomotives. Initially JR Freight continued to built locomotives originally designed by JNR with minor modifications, it created the new class of EF200, adopting the new classification rule with three-digit class names.

;Example: EH500-10

Usage of Roman letters is the same as for JNR usage. A hyphen is placed between the class number and running number.

; Class: Three digits of numerals are used to indicate classes. The classification by the maximum speed was replaced by the classification by the forms of power transmission and types of electric motors in case of diesel-electric locomotives.

:* 100–199 - Diesel-electric locomotives with DC motors:* 200–299 - Diesel-electric locomotives with AC motors:* 300–399 - Other diesel-electric locomotives:* 500–799 - Diesel-hydraulic locomotives

According to this numbering method, DF200-12 means locomotive number 12 of Class DF200, which is a class of diesel-electric locomotive with six driving axles and AC electric motors.

Shinkansen

All locomotives used on the Shinkansen system (for track maintenance and depot use) are diesel locomotives that are numbered with three-digit class names followed by a serial number connected with a hyphen. There have been two classes: 911 and 912.

In the uniform classification rule of Shinkansen rolling stock, the first digit 9 is assigned for cars and locomotives not for passenger use. In this 9XX group, the second digit 1 is for diesel locomotives.

See also

References

* [http://www.railway-museum.jp/exhibition/215.html Exhibition of Railway Museum: Number Plate]