Delay Attribution Guide

The Delay Attribution Guide contains a list of delay attribution codes and reasons. The same codes are used in Train Cancellation messages sent on the Train Movements feed.

The codes in use as of April 2021 are listed here for reference.

Codes are grouped in to several sections:

• A* - Freight Terminal Operations Causes
• D* - Holding Codes
• F* - Freight Operating Causes
• I* and J* - Infrastructure causes
• M* and N* - Mechanical or Fleet Engineer Causes
• O* - Network Rail Operating causes
• P* - Planned or excluded delays or cancellations
• Q* - Network Rail Non-Operating causes
• R* - Station Operating Causes
• T* - Passenger Operating causes
• V* - External events – TOC Responsibility
• X* - External events - Network Rail
• Y* - Reactionary Delays
• Z* - Unexplained delays and cancellations

Delay Attribution Codes

Code	Cause	Abbreviation
AA	Waiting acceptance into off Network Rail network Terminal or Yard	ACCEPTANCE
AC	Waiting train preparation or completion of TOPS list/RT3973	TRAIN PREP
AD	Off Network Rail network Terminal or Yard staff shortage including reactionary congestion caused by the shortage	WTG STAFF
AE	Congestion in off Network Rail network Terminal or Yard	CONGESTION
AG	Wagon load incident including adjusting loads or open door	LOAD INCDT
AH	Customer or off Network Rail network yard equipment breakdown/reduced capacity	YARD EQUIP
AJ	Waiting Customer's traffic including release information and documentation	TRAF DOC
AK	Safety incidents and mishaps (e.g. derailments, fire or chemical spill) in off Network Rail network freight yard or terminal (including private sidings, and stations – where it affects FOC services)	YARDSAFETY
AX	Failure of off network infrastructure (FOC or private)	OFFNET INF
AZ	Other Freight Operating Company cause, to be specified, in off Network Rail network terminals or yards	YARD OTHER
DA	Non Technical Fleet Holding Code	HOLD NT FL
DB	Train Operations Holding Code	HOLD T-OPS
DC	Train Crew Causes Holding Code	HOLD T-CRW
DD	Technical Fleet Holding Code	HOLD T FL
DE	Station Causes Holding Code	HOLD STN
DF	External Causes Holding Code	HOLD EXT
DG	Freight Terminal and or Yard Holding Code	HOLD YARD
DH	Adhesion and or Autumn Holding Code	HOLD AUTM
FA	Dangerous goods incident	DANG GOODS
FC	Freight Train Driver error, SPAD, Wrong routing or Missed AWS/DSD	FOC DRIVER
FE	Train crew not available including after rest	NO T-CREW
FF	FOC Diagramming or Rostering issue	FOC DIAG
FG	Driver adhering to company professional driving standards or policy	PRO DRIVER
FH	FOC Planning issue (not diagramming or rostering)	FOC PLAN
FI	Delay due to incorrect ETCS system or equipment operation by Driver	ETCS DVR
FJ	FOC Control decision or directive	FOC CONTRL
FK	Train diverted or re-routed at FOC request	DIVERT REQ
FL	Train cancelled at FOC request or planned not to run	CANCEL REQ
FM	Tail lamp or head lamp out or incorrectly shown	LAMP ISSUE
FO	Time lost en-route believed to be Operator cause and information required from Operator (Ops Responsibility)	LIR UNEX
FS	Delay due to ETCS/ ERTMS on-board overriding driver command	ETCS O-RDE
FW	Late start or yard overtime not explained by Train Operator	LATE START
FX	Freight train running at lower class or speed than planned classification or overweight	TRAIN SPEC
FZ	Other FOC causes incl. cause to be specified, including mishaps.	FOC OTHER
IA	Signal failure (including no fault found)	SIGNAL FLR
IB	Points failure (including no fault found)	POINTS FLR
IC	Track circuit failure (including no fault found)	TC FAILURE
ID	Level crossing faults and failure incl. barrow/foot crossings and crossing treadles	LEVEL XING
IE	Signalling functional power supply failure	SIG FUNC PWR
IF	Train Describer/Panel/ARS/SSI/TDM/Remote Control failure	PANEL FLR
IG	Block failure	BLOCK FLR
IH	Power supply and distribution system failure	PWR SUP DIS
II	Signalling lineside cable fault	SIG CABLE
IJ	AWS/ATP/TPWS/Train Stop/On-track equipment failure	AWS/ATP
IK	Telecom equipment failure (including no fault found)	TELECOMS
IL	Token equipment failure (including no fault found)	TOKEN FLR
IM	Infrastructure Balise Failure (TASS / ETCS / ERTMS)	BALISE FLR
IN	HABD/Panchex/WILD/Wheelchex fault, failure or mis-detection	HABD FAULT
IP	Points failure caused by snow or frost where heaters are fitted but found to be not turned on, not operative or defective	POINT HEAT
IQ	Trackside sign blown down, fallen over, missing, defective, mis-placed	TRACK SIGN
IR	Broken/cracked/twisted/buckled/flawed rail	RAIL FLAW
IS	Track defects (other than rail defects) inc. fish plates, wet beds etc.	TRACK FLT
IT	Rough ride or bumps reported - cause not known or no fault found	TRACK NFF
IV	Cutting or embankment earthslip, rock fall or subsidence (not the result of severe weather on the day of failure)	EARTHSLIP
IW	Non severe weather - snow/ice/frost affecting infrastructure equipment	INF WEATHR
I0	Telecom equipment legacy radio failure (RETB)	RETB FLR
I1	Overhead line/3rd rail defect	OHL/3 RAIL
I2	AC/DC trip (including no fault or cause found)	AC/DC TRIP
I4	OHLE/3rd rail power supply failure or reduction	SUPPLY FLR
I5	Possession over-run from planned work	OVERRUN
I6	Delays as a result of line blocks / track patrols (including late handback)	LINE BLOCK
I7	Engineer's train late into, from or failed in possession	ENGNRS TRN
I8	Animal Strike or Incursion within the control of Network Rail	ANIMAL
I9	Fires starting on Network Rail Infrastructure	INFRA FIRE
JA	TSR speed restrictions for track work outside of the Timetable Planning Rules	TSRNOT EAS
JB	Reactionary Delay to ‘P’ coded TSR	TSR REACTN
JD	Structures - Bridges/tunnels/buildings/retaining walls/sea defences (not bridge strikes)	STRUCTURES
JF	Off track asset defects or issues on the Network Rail network including fencing, gates, walkways, lighting (not due to vandalism or weather or where the asset is part of the station infrastructure)	OFFTRK ASS
JG	ESR/TSR due to works not completed or cancelled possession (where restriction did not exist prior to possession)	ESR/TSR
JH	Critical Rail Temperature speeds, (other than buckled rails)	HEAT SPEED
JK	Flooding not due to exceptional weather	FLOODING
JL	Safety related incident caused by maintenance or infrastructure staff oversight or error (not Operations staff)	SAFETY INF
JP	Failure to maintain vegetation within network boundaries in accordance with prevailing Network Rail standards, including where signals areobscured and a train strikes branches.	VEGETATION
JR	Delay due to RBC issues affecting ETCS / ATO operation (not balise related)	RBC ETCS
JS	Condition of Track TSR outside the Timetable Planning Rules	TRACK COND
JT	Points failure caused by snow or frost where heaters are not fitted.	NO PNT HTR
JX	Miscellaneous items on the track or railhead including litter, excluding leaves, demonstrated vandalism, weather or items fallen/thrown from trains	MISC OBJCT
J0	Telecom equipment radio failure (GSM-R)	GSM-R FLR
J2	Network Rail train dispatch equipment failure (including no fault found but excluding telecoms equipment)	TRTS FLR
J3	Axle Counter Failure	AXLE C FLR
J4	Infrastructure Safety Issue Reported by Member of the Public – No Fault Found	MOP NFF
J5	Infrastructure Asset Fault Reported but Proven to be mistaken	MIS REPORT
J6	Lightning strike against unprotected assets	LIGHTNING
J7	ETCS/ ERTMS Equipment Failure (excluding communications link and balises)	ETCS FLR
J8	Damage to infrastructure caused by on-track machine whilst operating in a possession	OTM DAMAGE
J9	Preventative Maintenance to the infrastructure in response to a Remote Condition Monitoring Alert	RCM ALERT
MB	Electric loco failure, defect, attention.	ELEC LOCO
MC	Diesel loco failure, defect, attention.	DIESL LOCO
MD	Other technical failures below the solebar	BELOW SBAR
ME	Steam locomotive failure/defect/attention	STEAM LOCO
ML	Wagons, coaches and parcel vehicle faults	WAGN/COACH
MN	Brake and brake systemsfaults; including wheel flats where no other cause had been identified	BRAKE/WHLS
MP	Rail/ wheel interface, adhesion problems (including ice on the running rail)	ADHESION
MR	Sanders and scrubber faults	SANDER
MS	Planned underpowered or shortformed service and or vehicle, incl. exam set swaps	ALOC STOCK
MT	Confirmed train borne safety system faults (not cab based)	SYST FAULT
MU	Depot operating problem	DEPOT OPS
MV	Engineer’s on-track equipment failure outside possession	ON-TRACK
MW	Weather - effect on T&RS equipment	WEATHR FLT
MY	Coupler and Coupler system faults	COUPLER
M1	Confirmed Pantograph ADD, shoe beam or associated system faults Incl. positive PANCHEX activations	PANTO/SHOE
M2	Delay due to ATO / ETCS equipment	ETCS
M7	Door and Door system faults	DOORS
M8	Other technical failures above the Solebar	ABOVE SBAR
M9	Reported fleet equipment defect - no fault found	FLEET NFF
M0	Confirmed train cab based safety system fault (including GSM-R)	CAB SAFETY
NA	On-train TASS/TILT failure	TASS/TILT
OA	Regulation decision made with best endeavours	ENDVR REG
OB	Delayed by signaller not applying applicable regulating policy	REGULATION
OC	Signaller including mis-routing (not ERTM /ETCS related)	SIGNALLER
OD	Delays due to national, regional or route operations directives, or route control decisions or directive	NR CONTROL
OE	Failure to lay Sandite or operate Railhead Conditioning train as programmed	RHC PROG
OF	Delay due to incorrect ETCS system or equipment operation by Signaller / Controller	ETCS CTRL
OG	Ice on conductor rail/OHLE	ICING
OH	ARS / TMS / SARS software problem (excluding scheduling issues and technical failures)	ARS / TMS
OJ	Fire in station building or on platform, affecting operators not booked to call at that station	STN FIRE
OK	Delay caused by Operating staff oversight, issues or absence (excluding signallers and Control)	OPTG STAFF
OL	Signal Box not open during booked hours	BOX CLOSED
OM	Technical failure associated with a Railhead Conditioning train	RHC FAIL
ON	Delays not properly investigated by Network Rail	MIS-INVEST
OQ	Incorrect Simplifier	SIMPLIFIER
OR	LOM Directive or signaller correctly applying local box instructions	BOX INSTR
OS	Late start or delays to Railhead Conditioning (RHC) or Ghost Train due to its own activity and not in reaction to another incident.	RHC LATE
OT	Operational Safety TSR implemented for sighting issues relating to foot crossings, level crossings or signals (Not vegetation caused)	SIGHT TSR
OU	Delays not investigated by Network Rail	NOT INVEST
OV	Fire or evacuation due to fire alarm of Network Rail buildings other than stations not due to vandalism	NR FIRE
OW	Connections held where the Prime Incident causing delay to the incoming train is a FOC responsibility incident and the next departing service is scheduled to depart less than 60 minutes later than the train being held.	FOC CONECT
OZ	Other Network Rail Operating causes	OPTG OTHER
PA	Published TSR associated with Planned Engineering Works where time loss is within Engineering Allowance	PLANND ENG
PB	Published TSR due to condition of asset (not associated with Engineering Work) where time loss is within Engineering Allowance	PLANND CON
PD	System generated cancellation (NOT to be attributed to manually)	SYSTM CANC
PF	Planned engineering work where a published diversion/SLW is not provided for in the schedule but where time loss is within Engineering Allowance	DIVRSN SLW
PG	Planned cancellation where that cancellation isidentified and agreed prior to 22.00 the day before the schedule runs	PLAND CAPE
PJ	Cancellation of a duplicate or erroneous schedule or an identified duplicate, false or erroneous delay (NOT berth off set related)	DUPLICATE
PL	Exclusion commercially agreed and documented between Network Rail and Train Operator	AGREED EXC
PN	VSTP service delays of under 5 minutes caused by regulation and or time lost in running (VSTP Schedule delay ONLY where that delay causes no reactionary delay)	VSTP DELAY
PT	Authorised TRUST reporting anomalies or inaccuraciesrelating to berth off sets	TRUST ANOM
QA	WTT Schedule and or LTP process including incorrect simplifiers (where produced by Capacity Planning).	WTT SCHED
QB	Planned engineering work- diversion/SLW not timetabled (outside the Timetable Planning Rules.)	DIVRSN/SLW
QH	Adhesion problems due to leaf contamination	RAILCONTAM
QI	Cautioning due to railhead leaf contamination	CAUTCONTAM
QJ	Special working for leaf-fall track circuit operation	LEAVES T/C
QM	Train Schedule VAR/STP process including incorrect simplifiers (where produced by Capacity Planning).	STP SCHED
QN	VSTP schedule / VSTP process (TSI created schedule)	VSTP SCHED
QP	Reactionary Delay to “P” coded Possession	PLND REACT
QT	Delay accepted by Network Rail as part of a commercial agreement where no substantive delay reason is identified	COMMERCIAL
RB	Passengers joining/alighting	PASSENGERS
RC	Pre-booked assistance for a person with reduced mobility joining/alighting	BKD ASSIST
RD	Attaching/detaching/Shunter/watering	ATT/DETACH
RE	Lift/escalator defect/failure	LIFT/ESC
RH	Station evacuated due to fire alarm	FIRE ALARM
RI	Waiting connections - not authorised by TOC Control	UNAUTH CON
RJ	Special Stop Orders - not authorised by TOC Control	UNAUTH SSO
RK	Waiting passenger connections authorised by TOC but out with TOC/Network Rail connection policy	AUTH CON
RL	Special Stop Orders authorised by TOC Control (including any delay at point of issue)	AUTH SSO
RM	Waiting connections from other transport modes	XTNL CONN
RO	Passengers taken ill on platform	PASS ILL
RP	Passenger dropped object whilst boarding/alighting from train and train delayed at TOC request	PASS DROP
RQ	Un-booked assistance for a person with reduced mobility joining/alighting	UBKD ASST
RR	Loading or unloading reserved bicycles	BIKE RSVD
RS	Loading or unloading unreserved bicycles	BIKE URSVD
RT	Loading excessive luggage	EXCES LUGG
RU	Locating lost luggage	LOST LUGG
RV	Customer Information System failure	PASS INFO
RW	Station flooding (including issues with drains) not the result of weather, where the water has not emanated from Network Rail maintained infrastructure/network	STN FLOOD
RX	Station delays as a result of overcrowding due to unplanned events or incidents (e.g result of line or station closure) where causal event is not determined.	UNPL EVENT
RY	Mishap - Station operating causes	STN MISHAP
RZ	Other Station operating causes	STN OTHER
R1	Incorrect train dispatch by station staff	DISPATCH
R2	Late TRTS given by station staff	LATE TRTS
R3	Station staff unavailable - missing or uncovered	STAFF MSNG
R4	Station staff split responsibility - unable to cover all duties	STAFF DUTY
R5	Station staff error - e.g. wrong announcements, misdirection	STAFF ERR
R7	Station delays as a result of overcrowding due to planned events(e.g.sports fixtures, concerts)	PLND EVENT
R8	Delay at Station believed to be Operator cause and information required from Operator (Station Responsibility)	STN UNEX
TA	Train-crew/loco/stock/unit diagram issues	DIAG ISSUE
TB	Train cancelled or delayed at Train Operator’s request	TOC REQEST
TF	Seat reservation problems	SEAT RESVN
TG	Driver	TOC DRIVER
TH	(Senior) Conductor/Train Manager	T-MGR/COND
TI	Train-crew rostering problem	ROSTERING
TJ	Tail lamp or headlamp missing, not lit or wrongly displayed	LAMP ISSUE
TK	Train catering staff (including Contractors)	CATERING
TM	Connection authorised by TOC but out with connection policy	AUTH CONN
TN	Late presentation from the continent	LATE CHUNL
TO	Time lost en-route believed to be Operator cause and information required from Operator (Ops Responsibility)	LIR UNEX
TP	Special Stop Orders	AUTH SSO
TR	Train Operating Company Directive	TOC DIRECT
TS	Delay due to incorrect ETCS system or equipment operation by Driver	ETCS DVR
TT	Autumn-attribution Neutral Zone delays (See Supplementary Autumn Attribution Guidance)	LF NEUTRAL
TW	Driver adhering to company professional driving standards or policy	PRO DRIVER
TX	Delays incurred on non-Network Rail running lines or networks including London Underground (except fleet related delays)	OTH NETWK
TY	Mishap-Train Operating Company cause	TOC MISHAP
TZ	Other Passenger Train Operating Company causes	TOC OTHER
T2	Delay at unstaffed station to non-DOO train	NONDOO STN
T3	Waiting connections from other transport modes	XTNL CONN
T4	Loading Supplies (including catering)	SUPPLIES
T8	Delay at Station believed to be Operator cause and information required from Operator ( Ops Responsibility)	STN UNEX
VA	Disorder, drunks or trespass	DISORDER
VB	Vandalism and or theft	VANDALISM
VC	Fatalities and or injuries sustained whilst on a platform as the result of being struck by a train or falling from a train	FATALITIES
VD	Passenger taken ill on train	ILL PASS
VE	Ticket irregularities or refusals to pay	TICKET IRR
VF	Fire caused by vandalism	VANDL FIRE
VG	Police searching train	POLICE-TRN
VH	Passenger Communication cord, door egress or emergency train alarm operated	PASS COMM
VI	Security alert affecting stations and depots	SEC ALERT
VR	Driver adhering to company professional driving standards or policies during severe weather conditions that are not fleet related	PRO DRIVER
VW	Severe weather affecting passenger fleet equipment including following company standards/policies or Rule Book instructions	SEV WEATHR
VX	External events occurring on the LUL or other non NR running lines	LUL CAUSES
VZ	Other passenger or external causes the responsibility of TOC	EXT OTHER
V8	Train striking or being struck by a bird	BIRDSTRIKE
XA	Trespass (Including non-intentional)	TRESPASS
XB	Vandalism or theft (including the placing of objects on the line)	VANDALS
XC	Fatalities or injuries caused by being hit by train (Including non-intentional)	FATALITIES
XD	Level Crossing Incidents including misuse and emergency services being prioritised over rail services.	XING INCDT
XF	Police searching the line	POLICE-RLY
XH	Severe heat affecting infrastructure the responsibility of Network Rail (excluding Heat related speed restrictions)	SEV HEAT
XI	Security alert affecting the Network Rail Network (including line blocks taken for emergency services attending an off Network Rail network incident)	SEC ALERT
XK	National Grid power failure - local area is also affected (includes ourages, surges and blips where a standby generator or UPS is installed and working)	EXTL POWER
XL	Fire external to but directly affecting the Network Rail network (including line blocks taken for emergency services attending an incident not directly affecting the Network Rail network)	EXTL FIRES
XM	External utility incident including gas, water mains and overhead power lines	GAS/WATER
XN	Road or crossing related incidents including cars on the line, crossing misuse and priority given to emergency services over trains (excluding bridge strikes)	ROAD INCDT
XO	External trees, building or structures encroaching or falling onto Network Rail network infrastructure (not due to weather or vandalism) also including aircraft and airport safety or operational related incidents.	EXT OBJECT
XP	Bridge Strike	BRIDGE HIT
XQ	Swing bridge open for river or canal traffic	BRIDGE OPN
XR	Cable vandalism or theft	CABLE VAND
XT	Severe snow or ice affecting infrastructure which is the responsibility of Network Rail (including implementation of Key Route Strategy)	SEV SNOW
XU	Sunlight on signal or dispatch equipment where all reasonable mitigation has been taken	SUN OBSCUR
XV	Fire or evacuation due to fire alarm of Network Rail buildings due to vandalism (not including stations)	VANDL FIRE
XW	High winds affecting infrastructure the responsibility of Network Rail including objects on the line due to the effect of weather	HIGH WIND
X1	Visibility in semaphore signalled areas, orspecial working for fog and falling snow implemented by Network Rail – in all signalling areas (including special working for level crossing visibility)	SPL WRKING
X2	Severe flooding beyond that which could be mitigated on Network Rail infrastructure	SEV FLOOD
X3	Lightning Strike – damage to protected systems.	LIGHTNING
X4	Blanket speed restriction or Key Route Strategy implemented in accordance with Group Standards or other national operational safety instruction	KRS / BLKT
X8	Animal Strike or incursion not within the control of Network Rail	EXT ANIMAL
X9	Points failure caused by severe snow or ice where heaters are fitted and working as designed	PNTS SNOW
YA	Lost path - regulated for train running less late	REG-ONTIME
YB	Lost path - regulated for another later running train	REG-LATE
YC	Lost path - following train running less late	FOL-ONTIME
YD	Lost path - following another later running train	FOL-LATE
YE	Waiting path onto/from single line	WTG S/LINE
YG	Regulated in accordance with Regulation Policy	REG INSTRC
YI	Late arrival of booked inward stock (inward and outward trains are operated under the same Track Access Contract)	INWD STOCK
YJ	Late arrival of booked inward train-crew (where the inward and outward trains worked by that train-crew are operated under the same Track Access Contract)	INWD CREW
YL	Waiting passenger connections within connections policy, contingency plan or otherwise agreed by NR/TOC	AUTHSD CON
YM	Special stop orders within the contingency plan or agreed by NR/TOC	AUTHSD SSO
YN	Service Recovery- booked train crew, not available	FIND CREW
YO	Waiting platform/station congestion/platform alteration	PLATFORM
YP	Delays due to diversions from booked route or line	DIVERSION
YQ	Passenger overcrowding caused by a train being of short-formation	SHRT FRMD
YR	Tactical cancellation for service recovery not caused by late running	SR CNCL
YU	Service Recovery- booked rolling stock, not available	UNIT SWAPS
YT	Reactionary delay to a train that is not leaving the network, by a train that is leaving the network	NON NR INF
YV	Tactical hold of a train at origin or at a strategic location en-route due to a line blocking incident on the train's booked route	HELD BACK
YX	Passenger overcrowding caused by delay or cancellation of another train or its own late running	OVER CRWD
ZS	No cause ascertainable for a Sub Threshold Delay causing Threshold Reactionary (where agreed by both Parties)	NOCAUSE AS
ZU	No Cause Identified After Full Investigation by Both Parties (A ‘Full Investigation’ will be one including all avenues of investigation agreed as reasonable by both Parties)	NOCAUSE ID
ZW	Uninvestigated Cancellations System Roll-Ups only	SYS CANC
ZX	Uninvestigated Late Start System Roll-Ups only	SYS L-STRT
ZY	Uninvestigated Station Overtime System Roll-Up only	SYS OTIME
ZZ	Uninvestigated Loss in Running System Roll-Up only	SYS LIR