DTAC denies its mobile signals interfere with BTS skytrain's traffic control system

[upu2]

The mobile operators can not just change frequency. The frequencies are regulated across the electromagnetic spectrum. Countries vary a little country by country but 2.4GHz is standard for the carrier along with 5GHz for the WiFi standard 'ac'

 

If the BTS has no allocated frequency which I find hard to believe then they need to request one from the Frequency Management body

 

Control systems are generally very low frequencies and probably don't extend beyond the VHF band if that

Edited June 26, 2018 by upu2

[Bangkok Barry]

3 hours ago, sungod said:

26 years ago  (where ever you come from) I bet you used to leave your doors unlocked whilst popping around the neighbors house for a cup of sugar.

 

I dont think the Thais have a monopoly on the behavior you describe even if it is true.Happens many places these days, but hey, lets bash them anyway 'cause its not like back at home.'

 

 

What on Earth has house security got to do with owning up and taking responsibility when something goes wrong? And where did I write that Thais have a monopoly of avoiding responsibility? Perhaps you were unable to properly comprehend what I wrote.

[Classic Ray]

5 hours ago, Muhendis said:

I am amazed that any mass transit system uses a relatively easily accessible wireless network to control it's systems. Thinking about terrorist activities, it must surely be more sensible to use fibre optics which are prone to neither hacking nor random stray interference.

Moving block signalling systems like that used in BTS depend on wireless radio signals to accurately position the train within the block of track it occupies. Fiber optics are used for train communication networks, but not for this purpose.

[Muhendis]

2 hours ago, Crossy said:

Fibre between stations is, of course, a given.

 

Lantau and Airport railway was nigh on 20 years ago (I worked on it too when I was with Cubic), at the time the airport trains were the world's fasted 1,500V DC trains at 135kph but not ATO IIRC.

 

CBTC is the latest (and greatest?) incarnation of ATO, it works very well for the short headways required of metro operation, provided the communication (the "C") is reliable.

 

My god. How time flies. Seems like only yesterday. Didn't see you there but then I wasn't looking too much.

[Muhendis]

39 minutes ago, Classic Ray said:

Moving block signalling systems like that used in BTS depend on wireless radio signals to accurately position the train within the block of track it occupies. Fiber optics are used for train communication networks, but not for this purpose.

Yup. Agreed, but any radio communication system is not and never will be infallible (as we have learned) especially when a wi-fi system used by the general public is incorporated into what amounts to a safety critical system. Wayside equipment need not be too much of an issue because the speed of the trains is not quite record breaking. I see no reason to disregard the use of trackside pickup loops and fibre optical links for this telemetry. 

Edited June 26, 2018 by Muhendis

[StreetCowboy]

3 hours ago, Crossy said:

Fibre between stations is, of course, a given.

 

Lantau and Airport railway was nigh on 20 years ago (I worked on it too when I was with Cubic), at the time the airport trains were the world's fasted 1,500V DC trains at 135kph but not ATO IIRC.

 

CBTC is the latest (and greatest?) incarnation of ATO, it works very well for the short headways required of metro operation, provided the communication (the "C") is reliable.

 

 

They (LAR Trains) were ATO.  I think track circuits to send the speed codes to the train, but not sure.

The CBTC is secure enough, but depending on the system used, may be subject to interference due to saturation of the signal from powerful transmitters near by.

[sungod]

4 hours ago, Bangkok Barry said:

 

What on Earth has house security got to do with owning up and taking responsibility when something goes wrong? And where did I write that Thais have a monopoly of avoiding responsibility? Perhaps you were unable to properly comprehend what I wrote.

I think most of us are unable to comprehend  what you have been writing in general. 

[Bangkok Barry]

6 hours ago, sungod said:

I think most of us are unable to comprehend  what you have been writing in general. 

 

Idiotic comment, like so many made on here.

[Crossy]

10 hours ago, StreetCowboy said:

The CBTC is secure enough, but depending on the system used, may be subject to interference due to saturation of the signal from powerful transmitters near by.

Input swamping by large out-of-band signals is my best guess at present too.

[Muhendis]

3 minutes ago, Crossy said:

Input swamping by large out-of-band signals is my best guess at present too.

Or maybe just a loose wire somewhere

[Crossy]

11 hours ago, Muhendis said:

My god. How time flies. Seems like only yesterday. Didn't see you there but then I wasn't looking too much.

We were located at the far end of the Mei Foo site area (out back of the container port), nice and quiet but right where the outfall from everyone's septic tank emptied. Our containers got "flooded" several times ?

 

[Cadbury]

Calling PM Prayut!!!

Pleeeeease........ pleeeeease...... come back home Prayut. We need you desperately to fix the problem!

Edited June 27, 2018 by Cadbury

[bluesofa]

3 minutes ago, Cadbury said:

Calling PM Prayut!!!

Pleeeeease........ pleeeeease...... come back home Prayut. We need you desperately to fix the problem!

Does that include importing an alien to fix the problem?

 

[mtls2005]

Seems odd that the problems start daily around 08:00 until mid-day then fine, then problems again around 16:00. And (according to reports) just around Siam is there potentially interference. TOT/DTAC have deployed 2300 MHz through the metropolitan area, and I've seen that new network in/around most BTS stations.

 

Not saying it can't be interference, but it seems the problem would continue throughout the day?

 

 

[lvr181]

1 hour ago, Muhendis said:

Or maybe just a loose wire somewhere

At "management" level?  

[Cadbury]

1 hour ago, bluesofa said:

Does that include importing an alien to fix the problem?

 

Wash your mouth out. Never! We are experts, we know how to fix!

[sungod]

Service on Sukhumvit is down to every 30 mins at the moment, long stops at each station.

[bluesofa]

7 minutes ago, Cadbury said:

Wash your mouth out. Never! We are experts, we know how to fix!

OK. Errr, is that with Thai or foreign soap?

Not sure which creates more bubbles and foaming at the mouth.

 

[mtls2005]

13 minutes ago, sungod said:

Service on Sukhumvit is down to every 30 mins at the moment, long stops at each station.

 

BTS Twitter: (they're also tweeting in English now) 

 

10.50 Due to the signal mandate system in Sukhumvit Line and Silom line, the process is still interrupted. This results in a moving train to Siam station at a low speed and a long train station. It is a 15-minute drive from the late arrival station. We apologize for the inconvenience.

 

The rain is probably not helping manual operation - just have to stop off to replace the wiper blades, and it messes up the smoke-signals.

 

 

[sungod]

43 minutes ago, mtls2005 said:

 

BTS Twitter: (they're also tweeting in English now) 

 

10.50 Due to the signal mandate system in Sukhumvit Line and Silom line, the process is still interrupted. This results in a moving train to Siam station at a low speed and a long train station. It is a 15-minute drive from the late arrival station. We apologize for the inconvenience.

 

The rain is probably not helping manual operation - just have to stop off to replace the wiper blades, and it messes up the smoke-signals.

 

 

I think they are using Google translate for their English tweets!

[mtls2005]

An apology from BTS FB page - it sounds like they have been a bit less than forthright until today.

 

They are currently installing a NEW signaling system, and are experiencing problems.

 

I don't recall hearing about this new system being installed now?

 

 

 

Mr. Surapong Laoha-Unya, Chief Executive Officer of Bangkok Mass Transit System Public Company Limited (BTSC) explained that the disruption to BTS SkyTrain services which severely affected passengers on Monday June 25th 2018, was a continuation of problems experienced over the past two weeks. In response the company has taken urgent steps to address root causes, enabling normal service to resume. The company would like to take this opportunity to express sincere apologies to our valued passengers for the inconvenience caused during such prolonged delays.

 

The cause of the recent failures is connected with the installation of a new radio signaling system, necessary to improve stability and support passenger services on the Green Line Extension from Bearing to Samut Prakan, scheduled for operation at the end of 2018. The new system is being installed at all BTS stations and in 52 BTS trains, and will be completed by Friday June 29th 2018. During the installation period intermittent failures have occurred which have affected train operations, however the company has implemented urgent measures to rectify the situation and will attempt to complete installation of the new signaling system within the deadline set. Over the past two weeks the automatic signaling systems of the BTS SkyTrain which are radio based, have experienced external interference especially around Phrom Phong, Asok and Siam Station, which is the interchange between the Silom and Sukhumvit Lines. 

 

As a result trains could not be operated as normal, resulting in service delays and passenger overcrowding, particularly during daily rush hours.

 

Mr. Surapong added that BTSC has closely investigated ways to resolve current problems, in order to restore the efficiency of BTS services and stability of the transport system. The company provides passengers with information updates on train delays through BTS social media channels, such as Twitter @BTS_SkyTrain, Line Application @Btsskytrain and our Facebook Page. 

 

Lastly, Mr. Surapong added “BTSC again apologies deeply for the recent service disruption and inconvenience caused to passengers. The company is closely monitoring the situation and resolving not only current issues but also other ongoing concerns. Providing convenient and punctual service is the main purpose of the BTS system and we have mobilised all possible resources to expedite resolution of current problems. Nevertheless, BTSC continues to strictly maintain safety standards in all aspects of our operations, which the company considers fundamental to serving our passengers.”

[TallGuyJohninBKK]

30 minutes ago, mtls2005 said:

An apology from BTS FB page - it sounds like they have been a bit less than forthright until today.

 

They are currently installing a NEW signaling system, and are experiencing problems.

 

I don't recall hearing about this new system being installed now?

 

 

I think you're absolutely correct, and that "little" detail was glaringly missing from all the public explanations I previously saw on the subject -- until now.

 

But I had been wondering, because some of their prior comment had talked about being able to improve the interference situation once the Samut Prakan line extension opens later this year -- which would make absolutely no sense IF the problem was merely radio congestion in and around Asoke, Siam, etc... 

 

BTW, I'm pretty sure I recall reading in the latest BTS annual report I read the other night that they already had a NEW signaling system installed back in 2011 or so...

[mtls2005]

In another newspaper, there is a long story which explains that there is no issue with the TOT/DTAC signals and that the problems are due to issues related to installing the new system, and perhaps, some interference issues in a few stations (Siam, Asok, Phrom Phong) from standard WiFi.

 

Yes, I think they installed a new signaling system back in 2009, or 2011, and had some problems at first. That's my recollection anyway.

 

 

[upu2]

17 hours ago, Muhendis said:

Yup. Agreed, but any radio communication system is not and never will be infallible (as we have learned) especially when a wi-fi system used by the general public is incorporated into what amounts to a safety critical system. Wayside equipment need not be too much of an issue because the speed of the trains is not quite record breaking. I see no reason to disregard the use of trackside pickup loops and fibre optical links for this telemetry. 

Safety critical systems are always hard wired. Use of radio systems is not allowed for them