Field guide
The railway’s words in plain English, and how Trainiac knows what it knows.
Start hereHow Trainiac’s data comes to beThe railway reports every train as it runs. Trainiac listens, keeps every word, and turns it into your journeys.Read it →
How Trainiac works
Where your journeys and their times come from
- Matching your journey to a trainYou say where and when; Trainiac finds the real trains that did it, and you pick yours.
- Frozen journeysYour journey is a copy of the train, kept in your account, so it never fades away.
- Older tripsTrainiac can only match a train it has a timetable for, and its timetable copies start in 2026.
- Imported ticketsYour Trainline bookings become journeys, each matched to the real train you were booked on.
- On this trainTwo journeys are on the same train when it’s the same run and your rides overlap.
- “Likely” train classThe timetable hints at what kind of train will run, and Trainiac reads the hint.
- Which time winsA real time beats a prediction, and a prediction beats the plan.
- How the live map places trainsNo train sends its GPS. Trainiac works out where each one is from the signalling, then keeps it moving smoothly.
- Routes on real trackYour journey is drawn along the actual rails, joined up from one timing point to the next.
Trains & services
What a train is called, and what it’s made of
- HeadcodeA train’s four-character name, like 1A23, that tells signallers what kind of train it is and where it’s going.
- Train UIDThe timetable’s own ID for a train’s schedule: a letter and five digits, like C12345.
- Train runOne train on one day: a schedule plus the date it ran.
- TRUST train IDA ten-character ID TRUST gives a train for the day, with its headcode inside.
- OperatorThe company that runs the train, known to the railway by a two-letter code.
- Train classThe model of train, given as a number: a Class 390 is a Pendolino, a Class 800 an Intercity Express Train.
- Multiple unitA train with its motors built into the carriages, so there’s no separate engine pulling it.
- FormationHow a train is made up: which units or carriages, how many, and in what order.
- Carriage numberEach carriage has its own number, painted on its side and usually by the doors inside.
- Empty coaching stockA passenger train running with nobody aboard, on its way to start a service or go to the depot.
- Freight trainA train carrying goods, sharing the same tracks and signals as passenger trains.
- VSTPA train planned too late to make it into the daily timetable file, sent out on its own instead.
- STP and overlaysHow the timetable says “this train is different on these days” without rewriting the whole thing.
Places
The railway’s many names for one spot
- CRS codeA station’s three-letter code, like PAD for London Paddington.
- TIPLOCThe timetable’s name for a place: up to seven letters, like PADTON for Paddington.
- STANOXA five-digit number for a place, used by TRUST when it reports trains.
- CORPUSNetwork Rail’s list of places that ties all their codes together.
- Timing pointA place in a train’s schedule where it has a time, whether it stops there or not.
- JunctionWhere railway lines meet or split.
- BerthA stretch of track on a signaller’s screen, usually the one leading up to a signal, which holds the headcode of the train in it.
- Signalling areaThe patch of railway one signal box or control centre looks after.
- SMARTNetwork Rail’s list of which berth steps mean a train arrived at, left or passed a place.
The timetable
The plan every train runs to
- CIF timetableThe timetable as data: every train’s schedule, published by Network Rail every day.
- Timetable changeTwice a year, in May and December, the whole timetable is replaced by a new one.
- Working timetableThe railway’s own, more detailed timetable, as opposed to the one passengers see.
- Half-minute timesWorking times can land on a half minute, written with an H on the end.
- Days runSeven ones and zeros that say which days of the week a schedule runs.
- PlatformWhere a train stops in the station. Planned ahead, but it can change on the day.
Live data
How the railway knows where trains are
- TRUSTNetwork Rail’s system that records when every train reaches its timing points.
- ActivationThe moment TRUST starts following a particular train for the day.
- Movement reportOne line from TRUST: this train, this place, this time, this many minutes late.
- CancellationTRUST’s record that a train won’t run, or won’t run all the way.
- Train DescriberThe part of the signalling that shows each train’s headcode moving along the signaller’s screen.
- Berth stepA train’s headcode moving from one berth to the next, because the train itself moved.
- DarwinNational Rail’s prediction engine: the brain behind the times on station departure boards.
- ForecastDarwin’s best guess at when a train will arrive or leave.
- Delayed, no estimateDarwin knows the train is late, but can’t yet say by how much.
- On timeWhat “on time” means depends on who’s counting.
Open data feeds
How all of it reaches apps like this one