Standard-gauge locomotives designation system


It may perhaps be helpful to keep in mind that, in Polish, lokomotywa (locomotive) is feminine, while parowóz (steam locomotive) is masculine.


1.     Steam locomotives




Current designation system for steam engines used by PKP was introduced in early 1920s and has remained unchanged until today. Each class is designated by one or two capital letters, one small letter and one-, two- or three-digit number, followed by a dash and service number (up to four digits).

First capital letter indicates locomotive type: O – passenger (in Polish, osobowy), P – express (pospieszny), T – freight (towarowy). Basically, diameter of drivers was the criterion: drivers above 1800 mm in diameter qualified the engine as an express one, 1500 to 1800 mm – passenger and below 1500 – freight. There were few exception, e.g. OKz32 tank engine was classed as a passenger one (an in fact served exclusively as such!) despite 1450 mm drivers.

Second capital letter K (derived from Polish kusy – literally ‘short’ in colloquial language) indicates a tank locomotive; otherwise this letter is omitted.

Third small letter indicates axle arrangement, namely:



Axle arrangement


Axle arrangement














one driven axle


1-2-0 or 0-2-1

2-2-0 or 0-2-2


2-2-1 or 1-2-2



1-3-0 or 0-3-1

not used

2-3-0 or 0-3-2



















not used

1-4-0 or 0-4-1

2-4-0 or 0-4-2



not used


not used*)



*) Reserved for narrow-gauge engines


Note that, contrary to British and American practice, number of axles rather than of wheels is used; e.g. 1-2-1 is equivalent to British 2-4-2 etc.

For locomotives built in Poland, number indicates the year in which the particular design was accepted; e.g. Pt31 indicates the 1-4-1 express locomotive accepted for service in 1931.

For locomotives of foreign origin, numbers 1 to 10 were reserved for German (in practice, Prussian ex-KPEV) machines and 11 to 19 for Austro-Hungarian ones. Within each group (type and axle arrangement) these numbers were assigned one after another, starting from 1 or 11, respectively, e.g. Tp1, Tp2, Tp3 etc. Again, there were few exceptions, mainly concerning Austro-Hungarian engines: in some groups, numbers from 1 to 19 proved insufficient and numbering was continued (e.g. Th24 was an Austrian, not Polish design). Another exception was Tr20, which was built by Baldwin, USA, against Polish order, but designated as an indigenous design.

Several tank engines were assigned number 100 (e.g. TKh100). Such designations referred to miscellaneous standard-gauge locomotives, taken over by PKP from various local railways, mainly German (Kleinbahnen, not DRG) and industry (mostly sugar plants). They were usually built for individual customers, as single examples or in very small batches. It was decided to group them in classes according to the wheel arrangement rather than distinguish each type.

Numbers above 100 were reserved for locomotives of foreign origin other than Prussian or Austro-Hungarian. Most of them were engines from German lands other than Prussia, from various German private railways, from German or Austrian military railways and from Russia. These classes were often represented by single examples and most of them were withdrawn before WWII. After 1945 this numbering was resumed, starting from 201, and included four classes: American and British wartime locomotives (Tr201, Tr202 and Tr203) and heavy American freighters purchased in 1946 (Ty246).

Contrary to what is sometimes encountered in foreign references, second (or third with tank engines) letter was always a small one and there was no dash: Ty51 has never been a ‘TY-51’ and so on.

Tenders are designated by a two-digit number indicating the water box capacity in cubic meters, capital letter corresponding to the number of axles (C – three, D – four) and numerical designation of the origin or year of acceptance – exactly as for engines. Thus e.g. 16C1 refers to a three-axle Prussian tender with 16 m3 water box capacity. This designation is followed by a dash and service number (up to four digits). If the tender was rebuilt so that its water box capacity changed, so did its designation; e.g. 32D43 with coal feeder became 27D43.

Industrial operators often designated tank locomotives by a two- or three-letter code (locomotive type and axle arrangement), followed by the serial number; e.g. TKb 2845 was the 0-2-0 tank freight engine with serial 2845 (Linke-Hofmann, 1925). Sometimes this designation is written with a dash, in this case TKb-2845. This system was, however, not obligatory. Tender locomotives used by ‘sand railways’ were designated in exactly the same manner as those in PKP service, with the only exception of Ty2s (ex DRG class 52), which had service numbers not assigned in any sequence, but simply corresponding to DRG numbers; e.g. Ty2-3458 was ex-DRG 52 3458. Some operators had their own designation systems.

Finally, it should be kept in mind that several preserved steam locomotives have been fitted with type and number plates taken from other examples, usually scrapped earlier. In some cases, PKP plates have also been fitted to engines previously used by industrial operators, which have never served with the state railways. I try to account for such cases when referring to individual examples.


1.     Electric and diesel locomotives






All electric and diesel locomotives in the PKP service are designated by two capital letters and a two-digit type number, followed by a dash and two- or three-digit service number.

First letter indicates drive type: E – electric (elektryczna), S – diesel (spalinowa – literally ‘internal combustion’).

Second letter indicates locomotive type: P – passenger (pasażerska), T – freight (towarowa), U – universal (uniwersalna), M – switcher (manewrowa). Typically, if a machine is rebuilt for service other than the original one, this letter is changed; e.g. a SM42 fitted with car-heating equipment became a SP42. Sometimes such reconstruction, or any major modernization, involves allocating a new service number, but this is not the rule.

Two-digit type numbers are allocated in succession within the following batches:

Electric locomotives:

01 to 14 – 3000 V DC, Bo’Bo’ axle arrangement,

15 to 19 – AC, Bo’Bo’ axle arrangement,

20 to 24 – 3000 V DC, Co’Co’ axle arrangement,

35 to 39 – AC, Co’Co’ axle arrangement,

40 to 49 – voltage or axle arrangement other than above.

Diesel locomotives:

01 to 09 – single control, mechanical transmission,

10 to 14 – multiple control, mechanical transmission,

15 to 24 – single control, hydraulic transmission,

25 to 29 – multiple control, hydraulic transmission,

30 to 39 – single control electric transmission,

40 to 49 – multiple control, electric transmission.

These numbers were allocated irrespective of the service type indicated by the second letter, so e.g. first line diesel freight locomotive with electric transmission and multiple control was designated ST43, as it was preceded by SM40, SM41 and SM42 switchers. It should also be noted that some of these blocks have not been used until today (there are no AC electric locomotives at all and no diesels with mechanical transmission and multiple control).

Prior to the introduction of this system in 1958, electric locomotives were designated by the letter E, followed by a number, initially corresponding to the service numbers batch allocated and then to the sequence of introduction; this applies to six classes. Diesel locomotives in the PKP service were designated by the LWe symbol (L – locomotive, W – diesel (from Polish wysokoprężny), e – electric transmission; there were probably provisions for another design features, never used in practice), plus two-digit number indicating the year of acceptance – as for steam locomotives. This system was used for just two classes. List of these designations is given below.


Before 1958

After 1958

E100 > E01

E110 > E02

E150 > E03

E200 > E04

E400 > E05

E500 > E06












The above-described system applies only to locomotives operated by PKP. Industrial and private operators are not obliged to use it, but sometimes they do. Many of them – e.g. sand railways – use factory designations followed by a service number; thus, 201E is equivalent to ET22, TEM2 to SM48 etc. Some switchers built by Fablok as type 6Da (SM42 in the PKP service) are designated Ls800 (derived from their rated power) plus serial number. Second-hand diesel and electric locomotives, purchased by private operators since 2003, have been designated in a number of ways and no unified system has been introduced. Many retain their original designations (e.g. M62s that correspond to the PKP class ST44). Details are given in individual entries.