deanparkr
Member
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- 23 Mar 2007
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- 41
ive always wondered why 444/450's squeak when they leave and enter a station?
What makes this happen ?
What makes this happen ?
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Why do Class 444's and 450's "squeak"
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Jord
Member
it's not just 444s/450s, also 350s
T
Tom
Guest
Not sure of the squeak you're on about - could well be the suspension on the units. The same occurs on 185s.
Incidentally the click just before stopping is interlocking kicking in ....
hock:
Incidentally the click just before stopping is interlocking kicking in ....
hock:
westcoaster
Established Member
might be the eeeeeeeeing coming from the traction motors
deanparkr
Member
- Joined
- 23 Mar 2007
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- 41
thats it!
the eeeeeeeeee eeeeeeeee
eeeeeeeee
eeeeeeeee
sound
lol
its really hard to describe!
T
Tom
Guest
You mean the warble? 
Not really that hard,
EeEeEeEeEeEeEeEeEeEeEeEeEeEeEe... *two middle coaches pass* EeEeEeEeEeEeEeEeEeEeEeEeEeEeEe...
Incidentally the click just before stopping is interlocking kicking in ....
Do you mean the sort of pressurized "pst" as the train slows to a stop in a station? (If so I've always wondered what that is, as it makes the noise whether or not the doors are released).
ChrisCooper
Established Member
The "wee-wee-wee-wee" sound is from the IGBT (Insulated Gate Bipole Transistor for anyone interested) control system for the motors. I have no idea the reason for the sound, most IGBT control systems just give of a constant "weeeeeeeeeeeee" when starting (compare Electrostars and 1995 tube stock on the Northern Line for two examples), so I don't know why the Desiros are different. Personally I think they sound daft, especially proper manly sounding EE507s on the slammers.
It's not the same as the "gear change" sounds on the Networkers, which is caused by older GTO Thyristor control systems, and to do with the inverters increasing the frequency of the motor supply in steps (IGBTs do it much smoother, so you don't hear the steps), infact it's closer to the whine those give when starting (also found on GTO Thyristor controlled DC motored trains like the 319s and 456s), which is caused by the rapid electronic switching of the power on and off to reduce the voltage when starting (and stops once full voltage is reached). Then again, even these can be made to sound strange, with some units and locos in other countries going through what sounds like musical scales as they move off, usually followed by "gear change" sounds.
It's not the same as the "gear change" sounds on the Networkers, which is caused by older GTO Thyristor control systems, and to do with the inverters increasing the frequency of the motor supply in steps (IGBTs do it much smoother, so you don't hear the steps), infact it's closer to the whine those give when starting (also found on GTO Thyristor controlled DC motored trains like the 319s and 456s), which is caused by the rapid electronic switching of the power on and off to reduce the voltage when starting (and stops once full voltage is reached). Then again, even these can be made to sound strange, with some units and locos in other countries going through what sounds like musical scales as they move off, usually followed by "gear change" sounds.
TheSlash
Established Member
Yeah but then other people get upset, normally Siemens' Managers
As Chris Cooper describes, it is just the frequency of the IGBT.
I suspect the sound does change as it accelerates, but the frequency changes to that of one outside the human ear spectrum.
andylloyd
Member
I thought there were modifications being carried out to stop the 'squeaking'?
Cheers
Andy
Cheers
Andy
T
Tom
Guest
You can't stop the warble ...
Key part of the traction package.
Although 444s sound like a warble mixed in with a Networker now....
Key part of the traction package.
Although 444s sound like a warble mixed in with a Networker now....
I believe that when the train reaches above a certain speed and the interlock clicks then all function of the door controls is totally locked out, where as below a certain speed ("pst" when slowing down) they're not. Could be wrong though.
The ones I use daily don't... :-?
Nathan
Member
- Joined
- 30 Jun 2005
- Messages
- 1,050
its part of its charectoristic!
T
Tom
Guest
It's not noticable on the inside of the train - but if you listen carefully it is on the outside.
Respite
Member
They "Squeak" because they are ****e, same as 175's clunk randomly....because they are also ****e......
Sorry just a bad day, drove 175's way too much & then when I was enjoying 158839 on return from chester some C**t threw a brick at Me & smashed the wiper off the unit along with various trim. I wanted to stop & go & beat the sh*t out of the little chicken ****es....Grrr................& breath...calm.....
Oh & 175's can make wierd "whooooing" noises but thats the hydrostatic brakes kicking in,retarding the unit & helping the discs cope with the brake demand.
Sorry just a bad day, drove 175's way too much & then when I was enjoying 158839 on return from chester some C**t threw a brick at Me & smashed the wiper off the unit along with various trim. I wanted to stop & go & beat the sh*t out of the little chicken ****es....Grrr................& breath...calm.....
Oh & 175's can make wierd "whooooing" noises but thats the hydrostatic brakes kicking in,retarding the unit & helping the discs cope with the brake demand.
westcoaster
Established Member
the click was set at 3mph but is now set higher at 7mph iirc, the mod was carried out just before i left, it was to keep the bell/ buzzer live for a few more seconds.
The 323s do make a different sound. Like "Eeeeee Eeeeee Eeeeeeeeeeeee" as it accelerates.
The 450 noise is just plan weird!
LittleRedTrain
Member
The noise did seem to change on them a few months back, can't describe exactly what the difference is, but it is noticeable to people like me who have to travel on the wretched things every day.
Yeah, though I do prefer 365/465s to that kinda sound as its more, I dunno how to put it...
16CSVT2700
Established Member
The 332s make a smooth eeeeeeeEEEEEEEEEEEEEEEEEEEEEEE sound from all traction packs (when working!)
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