Arl Loud Bang Question

[josephbloggs]

Hi folks,

I know there are a couple of posters on here who are very knowledgable about the ARL so I hope they can answer this for me.

When travelling, just past Ramkhamhaeng station (on the way to the airport) there are two loud bangs. They seem to be louder on the Express than the City trains. I know they have signs in the trains saying it is normal, but I would just like to know what it is. Anyone?

Cheers.

[dazk]

arcing electric perhaps

[josephbloggs]

arcing electric perhaps

No, it's not that. It's a physical thing that you can feel as the trains passes over it and you hear the bang.

[LennyW]

Detonator caps on the line to warn the drivers of an approaching hazzard, such as people working near the track. The yellow button sits on the line and the lead straps are bent around the rail to keep it in place. 1 bang, 2 bangs, 3 bangs etc have different meanings/levels of approaching hazzard.

[dazk]

Detonator caps on the line to warn the drivers of an approaching hazzard, such as people working near the track. The yellow button sits on the line and the lead straps are bent around the rail to keep it in place. 1 bang, 2 bangs, 3 bangs etc have different meanings/levels of approaching hazzard.

are you sure this is thailand warn! hazzard!

[josephbloggs]

Detonator caps on the line to warn the drivers of an approaching hazzard, such as people working near the track. The yellow button sits on the line and the lead straps are bent around the rail to keep it in place. 1 bang, 2 bangs, 3 bangs etc have different meanings/levels of approaching hazzard.

Thanks for the reply, very interesting! However, I don't think it's those. It happens on every single journey in exactly the same place and the train doesn't slow down at all as it would if there was a hazard. And it's more of a clunk than a bang. In fact clunk is a much more descriptive term - I should have used it my title.

[dazk]

Detonator caps on the line to warn the drivers of an approaching hazzard, such as people working near the track. The yellow button sits on the line and the lead straps are bent around the rail to keep it in place. 1 bang, 2 bangs, 3 bangs etc have different meanings/levels of approaching hazzard.

Thanks for the reply, very interesting! However, I don't think it's those. It happens on every single journey in exactly the same place and the train doesn't slow down at all as it would if there was a hazard. And it's more of a clunk than a bang. In fact clunk is a much more descriptive term - I should have used it my title.

bad joint in the track

[JAG]

From memory it happens just after a junction complex (several sets of points). As the track is mounted onto concrete rather than on timber sleepers set in stone chippings (ballast) I wonder whether it is some sort of device or sliding joint for coping with expansion in the rails?

[lomatopo]

_{My experience is limited to the Express train but I have noticed two loudish bangs in bound from the airport, but not out-bound to the airport. To me the sound appears to be coming from above so assume it has something to do with connections/aberrations in the concatenary (overhead electrification) system? It happens in the same two spots, which are many Km apart. I never really try to figure out exactly where these are, but will try on future trips. I still haven't figured out how they move trains down to the depot at Khlong Tan - there is some sort of spur near RCA on the north side, not sure if this has anything to do with the loud bangs?}

[SeaVisionBurma]

I have noticed this too - near Ramkamhaeng on every journey - as per the OP....2 loud bangs.

I am getting used to them - but you should see the tourists.

They jump about 3 feet in the air when it happens....

[IMA_FARANG]

I suspect...since you say it occurs at or near a junction of two tracks...that it is the the actual section of the track where the train switching is actually done.

The train has two possible routes to travel there...and the switching section is moveable to allow the train to travel either path.

So as the wieght of the train enters on to that switch section you get a CLUNK as the wieght of the train carriage enters it and the another CLUNK as the wieght of the train carriage exits that section.

If you were OUTSIDE the carriage you could probably hear a Clunk Clunk as the front of the carriage entered that section and a 2nd Clunk Clunk as the rear of the carriage exited that section.

INSIDE the train carriage you would feel a Clunk (Jolt) then another Clunk (jolt) seperated by the amount of time it took that carriage to enter and exit that switch section of the track.

P.S. The probable reason it is louder on the Express train than the Local train is that the express train is traveling faster?

[josephbloggs]

I suspect...since you say it occurs at or near a junction of two tracks...that it is the the actual section of the track where the train switching is actually done.

The train has two possible routes to travel there...and the switching section is moveable to allow the train to travel either path.

So as the wieght of the train enters on to that switch section you get a CLUNK as the wieght of the train carriage enters it and the another CLUNK as the wieght of the train carriage exits that section.

If you were OUTSIDE the carriage you could probably hear a Clunk Clunk as the front of the carriage entered that section and a 2nd Clunk Clunk as the rear of the carriage exited that section.

INSIDE the train carriage you would feel a Clunk (Jolt) then another Clunk (jolt) seperated by the amount of time it took that carriage to enter and exit that switch section of the track.

P.S. The probable reason it is louder on the Express train than the Local train is that the express train is traveling faster?

Hi,

No, I don't think it's that. The points/spur that Lomatopo mentions are between Makkasan and Ramkhamhaeng (but closer to Makkasan), and the trains do slow down for this but it's nothing like the loud clunks I'm referring to. These happen between Ramkhamhaeng and Hua Mark (maybe a km or so after Ramkhamhaeng station) when the trains are well clear of any points - it is just straight track.

And SVB is right - it does give people quite a shock. They do have small signs on the trains saying it's normal to hear those noises at that point but most people would never notice them. Still hoping to satisfy my curiosity and find out what causes them.....

Edit: Another reason I can say it's not that is because the two clunks are a reasonable distance apart - I'm guessing a few hundred metres - and are therefore definitely not the front carriage and the rear carriage passing the same thing.

[dantilley]

Sonic boom perhaps?

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