Fatal Train Crash In Belgium (5th June)

[sarahj]

When you travel to other countries, the signalling system always seems to look over complicated, well compared to the UK, where it is (in simple terms) straight forward......
G - DY - SY - R. and two whites for a shunt / calling on

Agreed. I guess you have to look at colour light systems, such as in Germany as just semaphores, but without the arms. until I understood German, i thought a yellow and a green showing was their version of a double yellow. I then found out it was showing a restriction over a point movement. (We would have a junction indicator here in the UK), and IIRC a 40 kmh limit over the point. Over the years bits have been added to, such a lit speed limits, white showing it applies now, yellow at the next signal, plus flashing aspects. I was trying to explain it to one person and said, we in the UK, it's almost speed based, but over in Germany it's route based. Mind I do like how their lit departure signal ZP9 is a green circle, ie the same as departure bat waved by a platform dispatcher/guard, while ours is a RA light.

I don't know Belgian signals, so cannot comment, but in Germany a distant is two yellows. Or yellow and green if the next signal is HP2, route change at next signal.

 

[axlecounter]

When you travel to other countries, the signalling system always seems to look over complicated, well compared to the UK, where it is (in simple terms) straight forward......
G - DY - SY - R. and two whites for a shunt / calling on

Mostly because you don't have speed signalling. That simplifies signals but makes lines knowledge much more complicated.
--- old post above --- --- new post below ---

I was trying to explain it to one person and said, we in the UK, it's almost speed based, but over in Germany it's route based.

I thought it was quite the opposite. hock:

 

[Flying_Turtle]

Belgium is pure speed with minimal direction indication and Germany is also speed but with a stronger direction indication.
--- old post above --- --- new post below ---

Correct. The British 'double yellow' aspect is unseen in Belgium... the two yellow lamps should be interpreted as a single yellow: the next signal is at danger.

And if the signal protects exclusively wrong line movements it will present the same aspects as in the normal direction but flashing. Thus the double yellow will be flashing double yellow on the wrong line

 

[TRAX]

Can I slightly go off-topic too so I can ask what are the differences between route signalling and speed signalling ?

 

[AlexNL]

Route signalling is what you find in the UK: the signal aspects tell the driver where he'll be going next (e.g. take a junction) but won't tell the driver how fast he can go. This depends on the driver's route knowledge, aided by lineside signs.

With speed signalling, it's the opposite: the signals tell the driver to slow down (e.g. by showing green-yellow in Germany) but won't tell the driver which way the signaller sends him next.

If a significant slowdown is needed (for example: a HST doing 125 mph has to take a junction which is designed for 40 mph max) there's no easy way to do this through route signalling: the signals don't have the aspects required to tell "Go down to 40 mph".

Instead, a system known as 'approach control' is used: the junction signal is held at red so that the driver gets some yellows first, expecting red. Only once he has approached the junction, the signal will clear (assuming that the block behind it is empty, of course).

 

[Flying_Turtle]

Can I slightly go off-topic too so I can ask what are the differences between route signalling and speed signalling ?

Route based you tell the driver the path he is going and from there he knows the speed. it is the case of the British signalling.
Speed based, you tell the driver at what speed he can run at each signal. It is the case of the american signalling where you have no indication of direction whataoever.

From this you can have different combinations of "strength" from route indication or speed indication. Belgium is a strong speed signalling with a weak route indication component as it just provides speed indications to drivers, but while generally not providing direction indications it will positively inform the driver when switches from normal line to wrong line and vice versa.

 

[edwin_m]

Instead, a system known as 'approach control' is used: the junction signal is held at red so that the driver gets some yellows first, expecting red. Only once he has approached the junction, the signal will clear (assuming that the block behind it is empty, of course).

In certain circumstances "flashing yellow" (or double yellow) or occasionally "splitting distant" signals are provided, which are a return to the principle of route signalling because they give the driver warning of a diverging route far enough ahead to adjust their speed accordingly.

 

[ComUtoR]

Not forgetting PRI's either. I also know that on some signals a Green will dictate a specific route too.

 

[TRAX]

That's much clearer now, thank you so much for the answers guys !

 

[ac6000cw]

It is the case of the american signalling where you have no indication of direction whataoever.

That's not quite true - although it varies from railroad to railroad, 'diverging' aspects are quite common e.g. 'Diverging Clear' or 'Diverging Approach', which at least tell the driver that the train is not taking the 'main' route through the interlocking (signalled junction layout). I think in some places 'splitting' (side-by-side) signal heads are/have been used where a more positive routing indication is desirable.

 

[Flying_Turtle]

That's not quite true - although it varies from railroad to railroad, 'diverging' aspects are quite common e.g. 'Diverging Clear' or 'Diverging Approach', which at least tell the driver that the train is not taking the 'main' route through the interlocking (signalled junction layout). I think in some places 'splitting' (side-by-side) signal heads are/have been used where a more positive routing indication is desirable.

Indeed but that you get pretty much in any system one way or the other.
And the diverging might be a junction or just a crossover, giving you a relative direction indication by the speed it indicates you (the diverging is a speed not a direction indication) not an absolute indication
But point here is: per rule there is no direction indication (most railroads don t have direction indicators!) although you can infer it.

 

[ac6000cw]

Indeed but that you get pretty much in any system one way or the other.
And the diverging might be a junction or just a crossover, giving you a relative direction indication by the speed it indicates you (the diverging is a speed not a direction indication) not an absolute indication
But point here is: per rule there is no direction indication (most railroads don t have direction indicators!) although you can infer it.

But why do you need direction indicators ?

(Note - direction is 'current of traffic' in this context, not a divergence/junction indication)

If you have two parallel tracks, both fully signalled for use in either direction, the Americans usually just treat them as independent single tracks with periodic connections between them (commonly called 'two main track CTC'). In practice the tracks might be normally used like a classic double-track line, with each track carrying trains predominately in one direction, but that is just for efficiency reasons.

 

[Flying_Turtle]

But why do you need direction indicators ?

(Note - direction is 'current of traffic' in this context, not a divergence/junction indication)

If you have two parallel tracks, both fully signalled for use in either direction, the Americans usually just treat them as independent single tracks with periodic connections between them (commonly called 'two main track CTC'). In practice the tracks might be normally used like a classic double-track line, with each track carrying trains predominately in one direction, but that is just for efficiency reasons.

Well... the americans also don t divide between shunt and trains... each railway is a railway! They might be parallel but may have different speeds; from one you be able to get to one siding and from the other you don't so they are effectively different directions although they take you to the same place!

 

[axlecounter]

It might be a simple historical reason, the driver needs to know where he's going, needs to know which side he should look for signals, etc... Or it might be that different regulations apply on left or right.

 

[edwin_m]

Are the signals for left hand running positioned to the left and those for right hand running to the right? If so then in the hours of darkness it would be possible to think you were on the other track and read across to the signals on the "wrong" side (as happened with the Norton Fitzwarren accident in the 1940s). A specific aspect for crossing to the other line alerts the driver to start obeying the other set of signals.

 

[Groningen]

With double track the signals are always on the outer side of the tracks. Or as in the Netherlands above the tracks. In Roosendaal and maybe south of Maastricht there are signs attached to the signal indicating the track for which the signal is valid.

Signal in Brussel with arrow.

 

[AlexNL]

In Belgium, signals that are for the "wrong" track (i.e. opposite to normal running) display flashing aspects. This should reduce the possibility of looking at the wrong signal.

 

[Flying_Turtle]

It might be a simple historical reason, the driver needs to know where he's going, needs to know which side he should look for signals, etc... Or it might be that different regulations apply on left or right.

For example, in Portugal, interlocked wrong line movements are limited to 160 km/h or even 100 km/h if you don't have a wrong line specific sectional appendix.
As i said earlier, certain double track sections may have different characteristics for each line like in Scotland, where the Largs branch is a double track where only one line is electrified) or the line does not have access to certain sidings or the layout at the next stion might not allow you to access the correct platform or even the branch line you are going.

 

[edwin_m]

In Belgium, signals that are for the "wrong" track (i.e. opposite to normal running) display flashing aspects. This should reduce the possibility of looking at the wrong signal.

Under some circumstances yes. But not if the train is on the right hand track in the dark, and the driver thinks he is on the left hand track and reads across to the signals on the left.

 

[axlecounter]

With double track the signals are always on the outer side of the tracks. Or as in the Netherlands above the tracks. In Roosendaal and maybe south of Maastricht there are signs attached to the signal indicating the track for which the signal is valid.

In Switzerland they may be on the outer side, above but to the left of each track or above in the middle of the two tracks (in tunnels). An arrow is used only when there are high risks of misunderstanding.

In Italy they're usually on the outer side. They use a different form of the signal to avoid confusion, a round one for signals to the left and a square one for signals to the right of the track. When necessary a lighted arrow is used. Note that it is interlocked, i.e. the signal won't clear if the arrow isn't lit!

 

[Flying_Turtle]

In Switzerland they may be on the outer side, above but to the left of each track or above in the middle of the two tracks (in tunnels). An arrow is used only when there are high risks of misunderstanding.

In Italy they're usually on the outer side. They use a different form of the signal to avoid confusion, a round one for signals to the left and a square one for signals to the right of the track. When necessary a lighted arrow is used. Note that it is interlocked, i.e. the signal won't clear if the arrow isn't lit!

Strangely familiar

 

[axlecounter]

Where is that?

 

[Flying_Turtle]

Where is that?

Portugal

 

[ac6000cw]

Well... the americans also don t divide between shunt and trains... each railway is a railway! They might be parallel but may have different speeds; from one you be able to get to one siding and from the other you don't so they are effectively different directions although they take you to the same place!

They differentiate between 'main' tracks and 'running' tracks e.g. the latter might run parallel to a 'main' track but exist primarily to provide access to industrial connections etc. and are quite often unsignalled so 'drive on sight' rules and low speeds apply (we would probably call them long sidings in the UK).

As for signal positioning, standard US practice seems to be (in a two track situation) to put the signals either on the outer sides, or overhead above the track centerlines.

Lower down this page - http://cs.trains.com/trn/f/111/t/212889.aspx?page=10#2879993 - are some pictures of modern 'two main track' CTC signals showing (on the left) a 'diverging clear' indication - red-over-green - for the train to go through the crossover to the other track. The lower head on the right hand post is not in use (turned through 90 degrees) since the crossover it will control is not installed/operational yet. 'Clear' (for the main route) would be green-over-red. If you replace green with yellow you get the equivalent 'approach' indications (prepare to stop at the next signal). If the signals have number or letter plates, they are automatic signals and 'stop and proceed' (permissive block) rules apply, otherwise they are controlled signals and a 'stop' is absolute.

(The above is a very simplistic description - some locations have three vertically stacked heads to provide more speed indications, and/or flashing aspects).

 

[Flying_Turtle]

I get you point. But that you get at any railway even if they have independent direction indication. In Portugal, if you get a double yellow or a fixed green with flashing yellow you are heading for a diverging track. The direction indication is there to tell you may infer where you are going if you have a couple or three different direction but at a large terminus you simply cannot know where you are ending up based on the signalling.
When one talks about direction indication one is talking about a signal that tells you directly where you are going.
for example, take a look at this Japanese starter signal:

You have no direction indicator but you have a very complete direction indication. The left most route is the Main route and the other two routes are to the right of the signal position. You do not infer but have an excat information at all times, independently of the points speed (in the US if you have a main and two diverging, where the diverging have the same speed you don't know to wich diverging you are going)