|
What arrangement did some of the electric trains from the 1990s and especially early 2000s that sounded like they had some 'gearbox arrangement', where the sound of the motor increased in pitch as the train got off the mark, then paused for a split second (like a gear change), then it started again as if in another 'gear' as it gained speed, then repeated again as it gained more speed.
The opposite always happened as the train slowed to a stop
The newer ones don't appear, at least audibly, to have the same motor 'arrangement'. Older electric trains, such as those built around 1989/90 and originally run on the Thameslink line were just of the 'one pitch' for a particular power level, essentially louder for more power / acceleration
|
What arrangement did some of the electric trains from the 1990s and especially early 2000s that sounded like they had some 'gearbox arrangement', where the sound of the motor increased in pitch as the train got off the mark, then paused for a split second (like a gear change), then it started again as if in another 'gear' as it gained speed, then repeated again as it gained more speed.
The opposite always happened as the train slowed to a stop
The newer ones don't appear, at least audibly, to have the same motor 'arrangement'. Older electric trains, such as those built around 1989/90 and originally run on the Thameslink line were just of the 'one pitch' for a particular power level, essentially louder for more power / acceleration
I was under the impression that East Midland back then, ran one and two car trains that were basically a diesel lorry, torque converter. At least, that's what they felt like. I expect someone will come along and tell us the model number.
I understand later, larger and hence heavier trains need too much torque for a mechanical gearbox and hence diesel-electric power.
|
What arrangement did some of the electric trains from the 1990s and especially early 2000s that sounded like they had some 'gearbox arrangement', where the sound of the motor increased in pitch as the train got off the mark, then paused for a split second (like a gear change), then it started again as if in another 'gear' as it gained speed, then repeated again as it gained more speed.
The opposite always happened as the train slowed to a stop
The newer ones don't appear, at least audibly, to have the same motor 'arrangement'. Older electric trains, such as those built around 1989/90 and originally run on the Thameslink line were just of the 'one pitch' for a particular power level, essentially louder for more power / acceleration
I was under the impression that East Midland back then, ran one and two car trains that were basically a diesel lorry, torque converter. At least, that's what they felt like. I expect someone will come along and tell us the model number.
I understand later, larger and hence heavier trains need too much torque for a mechanical gearbox and hence diesel-electric power.
Sorry, but my query was regarding pure electric trains. Looking back on it, I think the London Tube also has/had similar 'sounding' ones (definitely those running in the 2000s/2010s), namely the Jubilee Line ones, as if they are 'changing gear' when accelerating and stopping.
|
What arrangement did some of the electric trains from the 1990s and especially early 2000s that sounded like they had some 'gearbox arrangement', where the sound of the motor increased in pitch as the train got off the mark, then paused for a split second (like a gear change), then it started again as if in another 'gear' as it gained speed, then repeated again as it gained more speed.
The opposite always happened as the train slowed to a stop
The newer ones don't appear, at least audibly, to have the same motor 'arrangement'. Older electric trains, such as those built around 1989/90 and originally run on the Thameslink line were just of the 'one pitch' for a particular power level, essentially louder for more power / acceleration
I was under the impression that East Midland back then, ran one and two car trains that were basically a diesel lorry, torque converter. At least, that's what they felt like. I expect someone will come along and tell us the model number.
I understand later, larger and hence heavier trains need too much torque for a mechanical gearbox and hence diesel-electric power.
Sorry, but my query was regarding pure electric trains. Looking back on it, I think the London Tube also has/had similar 'sounding' ones (definitely those running in the 2000s/2010s), namely the Jubilee Line ones, as if they are 'changing gear' when accelerating and stopping.
My friend Google produced this:
-
Variable frequency control:
Electric trains often use variable frequency drives (VFDs) to control the speed and power of the electric motors. These VFDs adjust the frequency of the electrical current supplied to the motor, which in turn alters the motor's speed. The changes in frequency can create a sound that some people might interpret as gear changes.
|
What arrangement did some of the electric trains from the 1990s and especially early 2000s that sounded like they had some 'gearbox arrangement', where the sound of the motor increased in pitch as the train got off the mark, then paused for a split second (like a gear change), then it started again as if in another 'gear' as it gained speed, then repeated again as it gained more speed.
The opposite always happened as the train slowed to a stop
The newer ones don't appear, at least audibly, to have the same motor 'arrangement'. Older electric trains, such as those built around 1989/90 and originally run on the Thameslink line were just of the 'one pitch' for a particular power level, essentially louder for more power / acceleration
I was under the impression that East Midland back then, ran one and two car trains that were basically a diesel lorry, torque converter. At least, that's what they felt like. I expect someone will come along and tell us the model number.
I understand later, larger and hence heavier trains need too much torque for a mechanical gearbox and hence diesel-electric power.
Sorry, but my query was regarding pure electric trains. Looking back on it, I think the London Tube also has/had similar 'sounding' ones (definitely those running in the 2000s/2010s), namely the Jubilee Line ones, as if they are 'changing gear' when accelerating and stopping.
My friend Google produced this:
-
Variable frequency control:
Electric trains often use variable frequency drives (VFDs) to control the speed and power of the electric motors. These VFDs adjust the frequency of the electrical current supplied to the motor, which in turn alters the motor's speed. The changes in frequency can create a sound that some people might interpret as gear changes.
It seems YouTuber LU enthusiast Jago Hazzard (great name) has the answer:
www.youtube.com/watch?v=_4ANmUkGIJc
Apparently the thyristors that change the frequency you spoke of, and is unique to the Jubilee Line trains due to when they were designed / built.
Whether other 'overground' trains have similar devices that do the same (though not as loudly), I'm not sure, as it wasn't covered in the video.
|
|
|
|
