- If you want to learn to drive a train, there are simulators.
A screen, a set of controls, it's pretty realistic.
But that's not the only safety-critical job on the railway that needs training.
The signalers who decide where trains go are just as important,
making sure that every train goes down the right track
and dealing with disruption when it happens
so that passengers can still get where they're going.
You could simulate that in a computer, sure,
but there is a more physical approach.
Here in Darmstadt, Germany,
there is the world's most useful model railway.
- In this place, we started in 2006 at the Technical University in Darmstadt.
We had a similar facility since 1936.
We have about 500 square metres of space available
for the trainings, and a track laid out.
It's a fictional layout, 1.2 kilometres. We have some fictional names.
Some of the stations are named after persons
that helped developing this facility.
We are training actual signalmen here. They are taking exams here.
- So these are the oldest systems on the Deutsche Bahn network?
- Okay, yeah, it's right. It's mechanical interlocking.
Everything is worked manually.
The blue levers are for the points, the red levers are for signals.
- And that's our train? - Yeah, that's our train.
- And it's going that way. - This way, right track.
- Not into that tiny train.
- That's right. - Can come in, okay.
- Yeah, that's it. - Okay.
- So I have to know which points have to be turned.
It's point number one and two. So if you want to try it.
- So, yep. - You have to take it and turn it around.
- All the way down. - Just to lower position, yep.
- And, oh!
- It's turning over there.
- Yeah, that's it. - Okay.
- So we have also point number 7, 8, 9, and 10.
- Okay, so every time I do this...
- One point will turn.
Just a simulation. - Yes.
But it's an accurate one. - But it works like a real signal box.
- 'Cause in the real world, I would be pulling that
and that will be pulling through pulleys and levers
and actually physically switching the point.
- Yeah. - Making sure that
- That's it. - All right.
- So here we just have a computer who is turning the model points.
- Right, so you lock that into place,
it detects that I've done that, and the computer goes "pht".
- Yeah, that's it. - Okay.
So we've set the points, the next is safety interlock.
And that's a German thing?
- This is a German thing. Well, it's just common in German.
We have what we call a route locking.
So we want to open a special signal, so we have to take the right route lever,
which is called P2.
- Because it says 1, 2, 7, 8, 9, 10,
which is what I've just moved. - Yep, that's it.
- So do I pull up, down? - Down, down please.
- So this lever checks if all the points are set correct,
and second thing, he will lock all the points.
So we can't move them back.
- What happens if I were to pull the wrong lever?
- Just try it. - Right, okay.
- Try it, it won't work.
- Oh! - Just put it down.
- Oh! - It's closed.
- It's a physical lock. - Yep.
- I kind of assumed that was just going to beep at me
or complain, but that's an actual
physical interlock. - This is real, physical.
- Right, so now I can't even- - Yeah, try it.
It's not possible to pull them back. - You can't even close the lever.
- All at the same time. - Yep.
- Wow, okay. So that's-
- So this is an old computer.
It checks if everything is set at the right position.
- Wow, okay.
So we have put the points in position,
interlocked everything to make sure it's safe.
- That's right. - Can come in, okay.
- And then we just-
- Last step is put the signal to an off position.
It's P2. - Which is going to be...
- The P2. - P2, all right.
- Just like point levers to an off position.
[machine beeping]
And now the train driver sees a green signal,
and he can move on.
- But it takes a few seconds and the computer kind of simulates...
- It's a simulation, because he has to release his brakes
before he can start.
- So what's the last thing we need to do?
- So now we have to lock the line so another train can't follow.
So we have to tell us and the next signal box
there's a train on the line.
So we have to put down the button and to produce some electricity.
- Pull it down. - And 10 times, please.
[box whirring]
- So that would have sent a bell ringing or something
in another signal box saying we've got a train coming.
- Yep, that's it.
- So that's the manual ones. What came next?
- Interlocking, which is called electromechanical.
That's the next thing, which was about 50 years later.
- All right, let's do that.
- We've got the next station, which is an all-electric
interlocking from the 1950s.
Our train is coming, we see the red arrow.
It's a train intersection marker.
Train will stop at the entry signal of the station.
- Because that's a red and green light, and there's a red light there.
And this is the station. These are all the tracks, okay.
- So we can see all the tracks.
You can see in the direction of the points.
And now we want this train to enter into track number two.
So, now if you want to operate a point, we have to do a two button operation,
which means you have to push the button of the...
- And second one is this blue one.
Now it starts to blink. The point is turning.
And now it's on the left.
- And now it's on the left.
So the train is now going the right way.
So if there's nothing else in this section,
you can then turn that to green?
- Yep. So, we have to make an entry-exit operation.
We are starting at the entry signal
and we want to move into track number two.
There are two buttons.
- Right.
- Try it.
- So I have to push that one?
- Yep, and same time track number two.
- These two. - Yep, and nothing happens.
- Okay!
- Because we are missing two another points.
We have a flank protection, which is missing.
There might be a train waiting here
and he might just start to roll into our train.
- And he'll, right.
So I need to change that one as well.
So now there's no way that a train coming the other way-
- That's right. - Can come in, okay.
- And second point, we have to operate as point number one,
which is called the overlap.
So if a train won't stop at an exit signal...
- Yep, it'll derail there at the moment, won't it?
- Yes, and maybe he could hit another train,
so we have to reserve this space also for the train.
- Okay. So that one? - Yep.
Which is called the overlap.
- That's it. - All right.
- So, now try it again.
Entry exit operation. - Entry exit.
Lights up? Green light. - Lights up green light.
Train will enter in the next, I don't know, one, two minutes.
- And somewhere out there on the big model,
a train has started moving.
That's lovely. So that's the 1950s,
And this is all electrical circuits.
This isn't microcontrollers, this is all physical wiring.
- Or relay interlocking.
- There is really something in having that view
of what you're doing versus a screen
and a vague idea in a diagram.
Like, I can see the train pulling into the station.
That's lovely. So that's the 1950s,
and there's still some of this equipment out there.
- Of course. - That were being done
What's the most modern version?
- That's the computer interlocking. And now I will show you.
- Lead the way.
- All of the interlockings that you used today
are still in use in the German rail network.
The numbers, for example, of the mechanical interlockings
are dwindling at the moment.
In the future, all of them will be replaced
by electronic or computer interlockings.
The physical railway that you crash
will always stay in your mind,
even if it's a model train!
And you have the ability to get an overview
about the situation during any sort of disruptions,
not only the really focused view that you would have
during this disruption.
- So this is the future? - Yep, that's the future.
- So which train are we moving?
- We are try moving a train which is called 201.
- 201, okay. Yeah, I see it.
- So all you have to do is an entry exit operation, with a mouse.
- Oh, so just the single button push from earlier?
Everything else is automatic?
- Everything else is going automatically.
So first thing is you have to move the mouse pointer
to the red triangle on the right side, please.
It's the exit signal for the station.
And now move on to just one mouse click.
And now next train, please, on the right.
- The blue- - The blue one to the right.
That's the exit.
- And click that? - Click there.
- I don't know why I'm being so nervous.
It's a model train set. But in my head, this is serious.
So it's just done all the button pushes that I did earlier.
All the lever pulls. - Yep.
- Two mouse clicks.
- At the moment, nothing has operated.
It's just, "I want to go," from track number five onto the line.
- And it's doing all the interlocking?
- Yeah. - Making sure that
nothing's in the way. - And now have to tell
the computer, "Okay, I want to do it."
There's a button which is called in German "Verarbeiten" which means OK.
And after you push it, all the points are moving.
- All at the same time. - Yep.
And the signal is going to...
- And the signal's gone to green.
- Yep. That's it.
- It absolutely makes sense, but also it seems so much easier.
I know it's not. You've got exactly the same checks here.
- Of course. - That were being done
by the systems, that were being done by the circuits
and then being done by the physical interlocks.
But here it's code and we can see the train progress.
Like, the lights go red when there's a train in the section.
That's so clever.
- Big difference is I do have to operate 2, 3, 4, 5 stations.
[Tom laughs]
So it's not as simple as it looks like.
- You know the computer game?
- You have to do the same amount of work, just over a much bigger area.
Thank you so much. - Thank you.