Early this morning, some 50 people were evacuated from a Heathrow Express train that had broken down and got stuck in the tunnel near the airport. It was in fact a practice trial to test safety procedures, and the passengers were volunteers who thought the idea of walking through a railway tunnel in the early hours of the morning was an opportunity not to be missed.

An email went out to those who are likely to be interested — mainly local Heathrow staff, but a wide range of people had also turned up for the chance.

A recently joined Chaplain who works at the airport, a newly qualified Special Constable, a limousine chauffeur, made up just some of the crowd giving it a suitably mixed selection to test the evacuation.

Instructions were given to assemble at the Heathrow Express station in Heathrow by 11:30pm, for the practice to start at midnight. A leaflet offered some limited information about what was to happen, as part of the necessity is to be surprised by the event — leading to much speculation about whether we would have any smoke or pyrotechnics down in the tunnel.

A briefing from the leader of the operations repeatedly said “if” we are detrained, “if” we have to walk through the tunnels, “if” we have to climb up an emergency escape shaft.

If? We were only there assist in a serious test of emergency services for a chance to walk through tunnels and climb up emergency stairs. Much sniggering as each “if” was uttered, and briefing over — time to head down to the platform to await our doomed train.

A whole train to fill up with just 50 people, so being very British, the volunteers spread out to ensure none of us were sitting too close to each other, and some were delighted to wait for the fun to start in the luxury of first class.

The train headed off, and after a few minutes rolled to a slow halt. The fun had begun.

In fact, the fun in this case being sitting around for quite some time as the train driver issued reassurance that a fault had occurred, but everything was being dealt with.

After a while though, some more ominous warnings — the driver said that power to the overhead wires had been lost, and the train was now running on battery power alone. We might lose some services, and some lights might go out.

Then the air conditioning systems switched off, which was probably more significant than dimmed lights thanks to the sudden silence that accompanied it. The driver was now calling for Heathrow Express staff who might be on the train to contact him.

Throughout the drill, the driver said that we weren’t in danger, there is no danger, the train is not in danger, there is no danger, remain seated, wait for instructions.

Which unfortunately, started to hammer home Danger! Danger! Danger! Danger!

A post event feedback form suggested rewording that a bit.

Back to the drill, suddenly, all the lights in the train switched off. It wasn’t total darkness though, in part thanks to the lighting in the tunnel, but also, to the considerable amusement of the trapped passengers… the in-train televisions playing adverts were still running. Stuck in the dark, being told that we couldn’t use Oyster cards on the Heathrow Express was probably one of the more surreal moments of the night.

The lights were only off for a few minutes though.

At last the driver told us that we were going to have to get off the train. Bad news for ordinary passengers, for the volunteers, this was where the real fun begins.

In fact, it’s quite a mundane thing — as running along the tunnel is a pedestrian walkway. Quite narrow, but adequate for getting people off trains.

A short walk along the tunnels, and off to a side door where staff were on hand directing people.

This way Sir, up here Sir, that way Sir.

Necessary levels of calm professionalism to calm down the nerves of possibly quite alarmed passengers.

Up seven flights of concrete stairs, and after an hour of so in a train, fresh air.

In the dark we had to walk across a bit of field, and glow-sticks had been scattered in the grass to indicate the route to follow.

Two buses waited to ferry passengers back to Heathrow.

And that was it.

Test drill over for another year, and 50 increasingly tired volunteers headed back to the airport to fill in a questionnaire, and by 2:30am, started to head through a nearly empty airport homewards again.

Heathrow Express runs these drills about once a year, although some planned changes to operating procedures means that they have run two trials in the past year to test the new working methods.

Most of the volunteers were here simply because it’s a damn fun thing to do, although for members of emergency services, being a participant is often quite useful, to get a feel for the victim’s perspective in an incident.

They do occasionally run the trials in conjunction with the other emergency services as well, which tends to be a much larger event, but early this morning was a smaller test to make sure things work as they are supposed to.

For a lot of people, being given the chance to walk down a railway tunnel is an exciting experience. This morning was fun, and relaxed. How different it is when dealing with a packed train and anxious people who have meetings and planes to catch?

At least we know the procedures work. If they are ever needed.