Thread by @NetworkRailSE

“Why did my @Se_Railway train get held at Hither Green and another let in front of it? What is your signaller doing?!”
We get asked this occasionally, not always so politely, so we sat down with Dan the ops man for Kent to find out.
THREAD 1/

The way some trains are held and others let through is
called “regulating”. Junctions where trains meet each other are
“regulating points” and the principles are all written down for signallers at
each location and agreed with operators. 2/

In Kent (not so much Sussex, which has its own agreements)
trains are largely regulated for PPM (public performance measure) as that is
the metric that operators are measured by in the South East. This means a
train is within PPM if it is within 5mins of booked time. 3/

That means that if a train is 2mins late it will be held at a junction to allow an on-time train to pass, to protect that train’s punctuality. Which is fine if you are not on it. It can also have unintended consequences where the railway is very busy, as we shall see. 4/

.@se_railway will know some trains are vital because the stock has a tight turnround + the same with the crew. They get protected. There was a train on another part of our railway that carried 4 drivers as passengers each day and if it got held up it spread delays everywhere. 5/

But! Hither Green onwards is saturated with trains. If we regulate a Hastings train there when it’s 2mins late, it will lose 2mins, then be
regulated at Lewisham + New Cross and then it’s 10min late at London Bridge and everyone on it is upset. 6/

...Hence, sometimes Metro trains stopped at Hither Green will spot a blue train whistling past and wonder why. This map shows some of the places we make regulating decisions on Hastings to Cannon St trains + how difficult that can be. 7/

By the end of the year South East Route will be running 6,000 trains every weekday. That’s more than most countries. In some places the permutations of which train to regulate are so complex, nobody can understand it. So what can we do? 8/

We have a joint @se_railway / Network Rail performance team that analyses our trains, delay hotspots etc and we are always looking at improving timetables to give every train the best chance of a Right Time arrival. Then there is technology. 9/

Automatic Route Setting and Traffic Management software is being rolled out across our railway over the next few years. This will give signallers with the ability to predict the future by simulating what will happen and give them options when a train is waiting at a junction 10/

...Through using that software and putting operators’ priorities, stock + crew into it, we can get a better holistic view of our decisions and our passengers will get a better experience and hopefully feel less aggrieved when held at Hither Green. 11/

Finally, our junctions in London have trains over them every 2 minutes or less, so we measure ourselves on Right Time as that’s the only way of operating reliably and also the way that passengers actually judge us. Want to get involved? Click here: networkrail.co.uk/careers/
END