A run number is a four character, unique identifier assigned to every service, and by extension, to the train that is running that service.
In this article, 'n' is used to denote a number and 'a' is used to denote a captial letter.
Suburban Passenger Trains[]
This format is used by suburban passenger trains. It is also used for some intercity trains when required to differentiate trains with different loading gauges or other requirements. The number is composed of a roster and a trip. A train generally stays on the same roster for the whole day, and the trip increments each time the train changes direction.
Rosters are allocated in blocks:
| Roster | Usage |
|---|---|
| B1-99 | T7 Olympic Park Line (toward Blacktown, special event only) |
| L1-99 | T7 Olympic Park Line (toward Lidcombe) |
| S1-99 | T7 Olympic Park Line (toward Sydney, special event only) |
| 1-49
60-99 |
City Circle Lines (T2, T3, T8) |
| 50-59 | T5 Cumberland Line (4 car services) |
| 100-199 | Sector 3 (T1, T9) |
| 200-299 | Central Coast / Blue Mountains Lines (when operated by H set) |
| 300-399 | South Coast Line (services between Sydney, Wollongong and Pt Kembla) |
| 400-499 | South Coast Line (services between Sydney and Kiama) |
| 500-599 | T5 Cumberland Line (8 car services)
last 2 digits correspond to a 1-199 series roster that the train has come off |
| 600-699 | Sector 1 (T4) |
| 700-999 | Charter
Services altered due to trackwork |
For most rosters, the trip starts from A and increments. If required, it then usually jumps to XW, XX, XY, XZ (or similar). Because of the high number of trips on the T5 Cumberland and T7 Olympic Park lines, they usually start from AA.
To form the full run number, the roster and trip are combined with dashes added in between if necessary to pad it to 4 characters. For example, 3-XW is a sector 2 train on its 27th trip of the day.
Intercity/Regional Passenger & Inspection Trains[]
Format: annn or aann
The first letter usually shows which line/region the train is operating on or which line it is leaving Sydney using:
| Letter for normal runs | Letter for D set testing | Line |
|---|---|---|
| C | P/S | Coast = South Coast Line (trains to/from Sydney) |
| H | Y | Suburban area |
| K | P/S | Kembla = South Coast Line (trains not entering Sydney) |
| M | [Maintenance vehicle] | |
| N | A/Y | North = Central Coast Line |
| S | Southern Highlands Line | |
| U | 'Fake' train added to the system (by shorting together track circuits or applying a block at the signal box) to protect workers on track or for testing.
Can appear on both the suburban and intercity networks. | |
| V | Hunter Line | |
| W | G/R | West = Blue Mountains Line |
The second character usually indicates what type of train is being used:
| Character | Train Type |
|---|---|
| Any number 0-9 | Electric multiple unit (D/H/V set) |
| E | Electric locomotive |
| H | Any train being used for private hire |
| K | AK Cars |
| L | Diesel locomotive |
| M | Mechanised Track Inspection Vehicle |
| N | N set = Endeavour Train |
| P | P set = Xplorer Train |
| R | Any other Diesel Multiple Unit or Railcar |
| T | XPT Train |
| X | Complex shunting movement |
The last number is even for up trains (toward Sydney) and odd for down trains (away from Sydney), while the other numbers identify where the train is going. For example, SP35 is an Xplorer train leaving Sydney via the Main South Line, travelling to Canberra.
Heritage Trains[]
Format: nann
The first number identifies the operator of the train:
| Number | Operator |
|---|---|
| 5 | 3801 Limited |
| 6 | NSW Rail Transport Museum |
| 7 | Rail Motor Society |
| 8 | Lachlan Valley Railway Cowra |
| 9 | Sydney Rail Services |
The letter identifies the type of train:
| Letter (locomotive only) | Letter (when attached to other rolling stock) | Type |
|---|---|---|
| X | E | Any train with 1 or more electric locomotives |
| D | L | Any train with only diesel locomotives |
| R | Any Diesel Multiple Unit or Railcar | |
| Z | S | Any train with 1 or more steam locomotives |
The remaining two numbers are used to distinguish individual trains. As with the other formats, the last number is even for up trains (toward Sydney) and odd for down trains (away from Sydney).
Intrastate Non-Passenger Trains[]
Format: nnnn
The first number identifies the origin region of the train (see the map to the right). The second number identifies the destination region of the train. The third number provides more information about the operator and the narrows down the route of the train. The last number is even for up trains (toward Sydney) and odd for down trains (away from Sydney).
Interstate Trains[]
Format: naan
Note: NSW TrainLink trains do not use these numbers for interstate XPT services to Melbourne and Brisbane. They use the same regional passenger numbers for these services.
The first character is a number that show the day of the week the train departed at, with 1 = Sunday and 7 = Saturday. The second and third characters show the origin and destination of the train (each location is assigned to a letter). The last number is to differentiate two similar runs. The only rule is that if the last number is 8 then it must a passenger service.