Has anyone of you ever heard in some odl trains especially the metropolitan
ones that there is a noise after the accriage of a machine like a generator
that periodically starts and stops, and it lasts for a few seconds.

Is it some kind fan ?? i noticed this starts when a train starts has been
running for a while and it isnt met in new trains (so loudly at least)

cheers !!

Sorry i meant UNDER THE CARRIAGE !!

cheers

In message , Soniakostas
writes
Has anyone of you ever heard in some odl trains especially the metropolitan
ones that there is a noise after the accriage of a machine like a generator
that periodically starts and stops, and it lasts for a few seconds.

Is it some kind fan ?? i noticed this starts when a train starts has been
running for a while and it isnt met in new trains (so loudly at least)

cheers !!
Sounds like the compressors to me.
--
Clive.

"Clive Coleman" wrote in message
...
In message , Soniakostas
writes
Has anyone of you ever heard in some odl trains especially the
metropolitan
ones that there is a noise after the accriage of a machine like a
generator
that periodically starts and stops, and it lasts for a few seconds.

Is it some kind fan ?? i noticed this starts when a train starts has been
running for a while and it isnt met in new trains (so loudly at least)

cheers !!
Sounds like the compressors to me.
--
Clive.

Its the compressors which charge air for the brakes to work.

"Clive Coleman" wrote in message
...
Sounds like the compressors to me.

Almost certainly - but you'll only hear them if you're travelling in the
second or third cars of each four-car train. With the lack of motor noise
from those trailers (power is provided from the driving cars at each end)
the sound of the compressors is very noticeable.

"Jack Taylor" wrote in message
. ..

"Clive Coleman" wrote in message
...
Sounds like the compressors to me.

Almost certainly - but you'll only hear them if you're travelling in the
second or third cars of each four-car train. With the lack of motor noise
from those trailers (power is provided from the driving cars at each end)
the sound of the compressors is very noticeable.


Compressors are only mounted on the trailer (non-motor) cars.

They supply air for the braks (as mentioned), the doors and for the
automatic acceleration equipment on trains prior to electronic control.

In message , Brimstone
writes

Compressors are only mounted on the trailer (non-motor) cars.

They supply air for the braks (as mentioned), the doors and for the
automatic acceleration equipment on trains prior to electronic control.


Do the modern stock still use E.P. line breakers or is that job now done
by thyristors?
--
Clive Coleman

"Brimstone" wrote in message
...

"Jack Taylor" wrote in message
. ..

"Clive Coleman" wrote in message
...
Sounds like the compressors to me.

Almost certainly - but you'll only hear them if you're travelling in the
second or third cars of each four-car train. With the lack of motor
noise
from those trailers (power is provided from the driving cars at each
end)
the sound of the compressors is very noticeable.


Compressors are only mounted on the trailer (non-motor) cars.

That's what I said!

In message , Jack Taylor
writes
Almost certainly - but you'll only hear them if you're travelling in the
second or third cars of each four-car train. With the lack of motor
noise
from those trailers (power is provided from the driving cars at each
end)
the sound of the compressors is very noticeable.

There are motor non driving cars, or at least there were on "38" and
"62" stock, perhaps someone can let me know if this is still the case?
--
Clive.

"Clive Coleman" wrote in message
...
In message , Jack Taylor
writes
Almost certainly - but you'll only hear them if you're travelling in
the
second or third cars of each four-car train. With the lack of motor
noise
from those trailers (power is provided from the driving cars at each
end)
the sound of the compressors is very noticeable.

There are motor non driving cars, or at least there were on "38" and
"62" stock, perhaps someone can let me know if this is still the case?

'A' stock is formed DM+T+T+DM. The majority of units only have one cab
fitted for OPO - recognisable because the non-fitted cab does not have a red
end, the blue and white continues across the cab end. There is a small pool
of what are referred to as 'double-ended' units, which actually means units
where both cabs are OPO fitted (and both cabs have red ends), which are the
only units that can be used on the Chesham shuttle and the ELL (sets
5056-5066, 5088-5122 and 5232).