A Retail Service ID (RSID) is an 8-character code that uniquely identifies a train on any one day. Its purpose is to link a train in a timetable enquiry with the same schedule in the Reservations Service. The RSID is only used in rail retail systems so it will not appear in timetable data sourced from elsewhere.
The first two characters represent the owning TOC, then there is a four-digit number, with a final two digits to identify the portion if the train splits or joins en route.
The constituent parts of the RSID are contained within the timetable data published by ITPS and here is a simple example of a Kings Cross to Edinburgh train…
Y60631 161212 170519 1111100 PXX 1S13 6240 121700001___E410 125EP
BXGR Y
KNGX 1100
YORK 1250 1253
DLTN 1319 1321
NWCSTLE 1349 1352
EDINBUR 1517
The GR TOC code on the second line of the train schedule is married with the 4-digit number that appears immediately after the 1S13 Train Identity: 6240. As this train does not split/join there is no Portion ID in the source schedule so “00” is substituted. The complete RSID is then inserted into the second line of the amended train schedule that is supplied to PMS and retail systems: GR624000…
Y60631 161212 170519 1111100 PXX 1S13 6240 121700001___E410 125EP
BXGR Y GR624000
KNGX 1100
YORK 1250 1253
DLTN 1319 1321
NWCSTLE 1349 1352
EDINBUR 1517
In the next case we see a Victoria to Littlehampton train that splits at Haywards Heath, with a portion going to Eastbourne. Two separate train schedules are published by ITPS, with an association record (not shown here) that tells a journey planner how the two schedules are related…
L02999 170102 171208 1111100 PXX 1H30 2214 124746000 1 EMU100D
BXSN Y
VICTRIC 1517
CLPHMJC 1522H 1523H
ECROYDN 1532 1533H
GTWK 1547H 1549
HYWRDSH 1559 1603
BURGESH 1608H 1609H
HOVE16201621
SHRHMBS 1626H 1627H
WORTHNG 1633 1634
WWRTHNG 1635H 1636
DRNGTOS 1638 1638H
GORNGBS 1640H 1641
ANGMRNG 1644H 1645
LTLHMPT 1656
L02305 170102 171208 1111100 PXX 1F34 2214 124746000 2 EMU100D
BXSN Y
HYWRDSH 1606
WVLSFLD 1610 1610H
PLMPTON 1616 1616H
LEWES 1623H 1624H
POLGATE 1636 1637
HMPDNPK 1640H 1641
EBOURNE 1646
In the schedules above, the TOC Code (SN) and 4-digit number (2214) appear as before, but there are additional portion IDs: 1 & 2; immediately before the “EMU” motive power type.
The complete train runs from Victoria so the two portions IDs are added together (with a preceding 0). The combined RSID, with the summated portions, is then SN221403…
L02999 170102 170519 1111100 PXX 1H30 2214 124746000 1 EMU100D
BXSN Y SN221403
VICTRIC 1517
CLPHMJC 1522H 1523H
ECROYDN 1532 1533H
GTWK 1547H 1549
CR HYWRDSH XX1H3022141247460001EMU100DB SSN221401
HYWRDSH 1559 1603
BURGESH 1608H 1609H
HOVE16201621
SHRHMBS 1626H 1627H
WORTHNG 1633 1634
WWRTHNG 1635H 1636
DRNGTOS 1638 1638H
GORNGBS 1640H 1641
ANGMRNG 1644H 1645
LTLHMPT 1656
At Haywards Heath the train splits, with the front portion going forward to Littlehampton. At this point the RSID changes to SN221401, whilst the rear portion goes to Eastbourne with the RSID being SN221402…
L02305 170102 170519 1111100 PXX 1F34 2214 124746000 2 EMU100D
BXSN Y SN221402
HYWRDSH 1606
WVLSFLD 1610 1610H
PLMPTON 1616 1616H
LEWES 1623H 1624H
POLGATE 1636 1637
HMPDNPK 1640H 1641
EBOURNE 1646
The different portion IDs allow the reservations system to offer seats in the correct part of the train for any journey:
- SN221403: For passengers travelling no further than Haywards Heath – all coaches
- SN221401: For passengers travelling to stations Burgess Hill-Littlehampton – front portion only
- SN221402: For passengers travelling to stations Wivelsfield-Eastbourne – rear portion only
The 4-digit number and Portion ID are input by the owning TOC at the Train Planning stage. Generally, the main train will be portion 1, with the splitting or joining portion being 2. For trains that have more than two portions (such as the Euston-Inverness/Aberdeen/Fort William Sleeper) the same principals apply, but with a more complex portion numbering system: 1, 2, 4, 8.
Warning: Changing the 4-digit number or Portion ID after the train has first been published by ITPS can cause problems in the Reservations System – which can then prevent the sale of advance purchase tickets and reservations. Train operators need to ensure that the correct codes are input from the outset. This would also be the case should a franchise change result in the use of a new 2-alpha TOC code in the middle of a timetable period.
The screen shot below shows how the RSID and its constituent parts, for the Victoria to Littlehampton train, appear when the train schedule is viewed in PMS. The 4-digit number is in the Headcode field as a consequence of how the RSIDs were accommodated in a data field in train planning systems which is rarely used for its original purpose:
