busfan4022 Posted February 16, 2011 Report Share Posted February 16, 2011 Can some please explain this? I was riding 4075 on the #14, and whenever it reached speeds exceeding 15 or so mph it created an ear-splitting noise that sounded as if someone was literally starting up a chainsaw in the back. I recorded a short vid of it posted below. It's obvious that something is clearly wrong with this bus, I'm just curious as to why CTA let this bus do its run even though it sounded as horrible as it did. The audio is kinda poor, but this bus was REALLY loud, it scared me so bad when I first heard it. Anyone have any take on this? Vid: http://tinypic.com/r/4k9zt3/7 Quote Link to comment Share on other sites More sharing options...
artthouwill Posted February 16, 2011 Report Share Posted February 16, 2011 Can some please explain this? I was riding 4075 on the #14, and whenever it reached speeds exceeding 15 or so mph it created an ear-splitting noise that sounded as if someone was literally starting up a chainsaw in the back. I recorded a short vid of it posted below. It's obvious that something is clearly wrong with this bus, I'm just curious as to why CTA let this bus do its run even though it sounded as horrible as it did. The audio is kinda poor, but this bus was REALLY loud, it scared me so bad when I first heard it. Anyone have any take on this? Vid: http://tinypic.com/r/4k9zt3/7 Haven't had a chance to listen to the vid yet. Do you regularly ride the artics? You know these are hybrid buses and sometimes the "motors" sound very loud and whiney. The only other "chain saw" like noise I can think of, I've heard on several NABI pace buses and some CTA Nova buses. I heard it once on a motorcoach bus I was driving. I got my bus switched out because I felt something was severely wrong with it. As it turned out, when the mechanic got it back to the garage, they had to tow it in the shop, something about the rear end "going out". Quote Link to comment Share on other sites More sharing options...
sw4400 Posted February 16, 2011 Report Share Posted February 16, 2011 Can some please explain this? I was riding 4075 on the #14, and whenever it reached speeds exceeding 15 or so mph it created an ear-splitting noise that sounded as if someone was literally starting up a chainsaw in the back. I recorded a short vid of it posted below. It's obvious that something is clearly wrong with this bus, I'm just curious as to why CTA let this bus do its run even though it sounded as horrible as it did. The audio is kinda poor, but this bus was REALLY loud, it scared me so bad when I first heard it. Anyone have any take on this? Vid: http://tinypic.com/r/4k9zt3/7 It's hard to say if this "whine" is normal or not honestly, busfan4022. I've heard similar "whines" while riding a few TMC's, Flxible 5300's, and NOVA LFS's in the past. Quote Link to comment Share on other sites More sharing options...
Guest DevalDragon Posted February 16, 2011 Report Share Posted February 16, 2011 Doesn't sound like any chain saw I've ever heard. But it does sound like some hybrid buses I've been on. Can some please explain this? I was riding 4075 on the #14, and whenever it reached speeds exceeding 15 or so mph it created an ear-splitting noise that sounded as if someone was literally starting up a chainsaw in the back. I recorded a short vid of it posted below. It's obvious that something is clearly wrong with this bus, I'm just curious as to why CTA let this bus do its run even though it sounded as horrible as it did. The audio is kinda poor, but this bus was REALLY loud, it scared me so bad when I first heard it. Anyone have any take on this? Vid: http://tinypic.com/r/4k9zt3/7 Quote Link to comment Share on other sites More sharing options...
Archon Posted February 16, 2011 Report Share Posted February 16, 2011 Could also be a turbo charger going they can get very loud and scream at times Quote Link to comment Share on other sites More sharing options...
busfan4022 Posted February 16, 2011 Author Report Share Posted February 16, 2011 I ride arctics nearly everyday. It definitely wasn't normal. Just sounded like something was well...wrong. I thought something maybe slipped in the transmission or something, but what do I know? I'm not a mechanic. But the sound did progressively get louder as the bus went faster then faded away softly as it reached a steady speed on L.S.D. The only other sound comparison I can think of was the brake chargers that sound sort of like a fax machine when these buses make a hard stop after going fast. But even then, this definitely isn't the case. Quote Link to comment Share on other sites More sharing options...
Busjack Posted February 16, 2011 Report Share Posted February 16, 2011 I listened to the video and was not sure about what your were noting. If it is the whine, that seems typical, although I don't know about the volume. However, I also heard a ratcheting or rattling sound. 1 Quote Link to comment Share on other sites More sharing options...
speedracer1407 Posted February 19, 2011 Report Share Posted February 19, 2011 Yes, the artics make some odd noises at seemingly random times, but if you ride them frequently, as I did every day until recently, it's pretty easy to learn the noises' patterns and when to expect them. This is definitely not normal, thought it isn't necessarily an impending mechanical disaster. It's clear that, in the video, the bus was accelerating from a stop, and the volume/tone of the noise did not scale with the acceleration of the bus, so it's probably not anything related to internal transmission or engine components. However, the artics have a chorus of what sound like fans that kick on and off depending on speed and load while accelerating (and then an even louder chorus during brake regen). I'd wager a reasonable sum that this noise is a cooling fan component (bearing or motor) that's failing. Here's why: The artics have a predictable sequence of noises when accelerating off the line. The first few seconds is all electric power. By 10 MPH or so, the diesel wakes up and begins adding power gradually (listen carefully, and you can hear the turbo spool up early-on). By 20 MPH or so, the diesel is working under high load, and various cooling fans (or what sounds like fans, anyway) spool up and stay spooled until the driver lifts off the pedal, at which point both the diesel and the fans go relatively quiet. Seems to me like this sequence describes the noise in the video with a faulty fan component (or whatever it actually is). 1 Quote Link to comment Share on other sites More sharing options...
busfan4022 Posted February 21, 2011 Author Report Share Posted February 21, 2011 Thanks speedracer for shedding some light on the subject. I somehow managed to ride #4075 AGAIN on the 14 on Friday morning. This time, it seemed as though the issue was fixed from the beginning of the route up until LSD. Once the bus hit top speed the "cooling fan" once again started to act erratic. This time, much more unusual than the first because instead of the sound fading away at top speeds, it instead just seemed to stop and then go again. I managed to take a better video to correctly portray just how bad this bus sounds. New Video: http://tinypic.com/r/2i1k3mv/7 (the sound was so bad it made passenger's head turn, you can even hear a lady complaining in the background) However, I also heard a ratcheting or rattling sound. Completely normal for these buses, that sound comes from either the overhead light panels, or the vibration of the seats in the arctic joints. It sounds like not too many of you ride these buses often. Quote Link to comment Share on other sites More sharing options...
sw4400 Posted February 21, 2011 Report Share Posted February 21, 2011 Thanks speedracer for shedding some light on the subject. I somehow managed to ride #4075 AGAIN on the 14 on Friday morning. This time, it seemed as though the issue was fixed from the beginning of the route up until LSD. Once the bus hit top speed the "cooling fan" once again started to act erratic. This time, much more unusual than the first because instead of the sound fading away at top speeds, it instead just seemed to stop and then go again. I managed to take a better video to correctly portray just how bad this bus sounds. New Video: http://tinypic.com/r/2i1k3mv/7 (the sound was so bad it made passenger's head turn, you can even hear a lady complaining in the background) Definately sounds weird, but kinda like #4484 sounded. Only thing was that #4484 sounded like that the moment the operator stepped on the gas until it was taken off again. It is probably a fan motor of some sorts, but if it's what you'd call a "defect", I don't think it is. #4075 is a 2009 New Flyer Model, and being 2 years old and probably already having close to, if not over 100,000 miles on it, it's probably common to have problems like this occur. Quote Link to comment Share on other sites More sharing options...
speedracer1407 Posted February 21, 2011 Report Share Posted February 21, 2011 Wow, that sounds like it would make for an irritating ride to work. If it's a fan component, which it sounds like it is, I wouldn't necessarily call it a "defect." Just one of many components that wear out and fail from time to time. As a side note, I certainly miss flying down LSD on the 147 at top speed, knowing that I was making rapid progress to the office. Now it's the Red Line, which doesn't make rapid progress anywhere. Quote Link to comment Share on other sites More sharing options...
OSUITS Posted February 24, 2011 Report Share Posted February 24, 2011 I second (or fourth or fifth) the fan, fans are usually powered by hydraulics not electric so the fan speed is dependent on engine speed. Since the bus under only electric until 15 mph or so the fan is at low speeds, as the engine spools up, so does the fan. More than likely the fan solenoid got stuck on so the fan is always on. From the outside of the bus it sounds like the bus is powered by jet engine. Quote Link to comment Share on other sites More sharing options...
MVTArider Posted February 24, 2011 Report Share Posted February 24, 2011 I haven't heard any sounds like that on Metro Transit's 2007/08/09/10 diesel New Flyer artics. The rattling however is definitely normal. Probably a fan as others have stated. I can see why you are curious about it! Quote Link to comment Share on other sites More sharing options...
speedracer1407 Posted February 24, 2011 Report Share Posted February 24, 2011 I second (or fourth or fifth) the fan, fans are usually powered by hydraulics not electric so the fan speed is dependent on engine speed. Since the bus under only electric until 15 mph or so the fan is at low speeds, as the engine spools up, so does the fan. More than likely the fan solenoid got stuck on so the fan is always on. From the outside of the bus it sounds like the bus is powered by jet engine. Fans powered by hydraulics? I'm skeptical about that that for 2 reasons: Firstly, a hydraulic system powering multiple components (there are a lot drivetrain-related fans on these artics) is inherently way more complicated and prone to mechanical failure than electric fans. This seems like a really weird engineering solution, especially in a drivetrain with robust electric capabilities. Secondly, in the 2nd video, the failed fan component (if that's what it is) spools up and down repeatedly during steady-state acceleration. If, as you say, hydraulic fans are dependent on engine speed, the offending fan would be producing its awful noise more steadily, since you can also hear that the engine is under steady load and RPM while accelerating and maintaining speed on LSD. And even if the engine RPM rose and fell during steady cruising (which doesn't seem to be the case in the video), it certainly wouldn't do so as much as that noisy fan seems to. Hydraulic fans that scale with engine speed are news to me. Doesn't mean there isn't a hydraulic component to their actuation, but I'd be really surprised if they were operated entirely with hydraulics AND scaled with engine speed. Quote Link to comment Share on other sites More sharing options...
OSUITS Posted February 24, 2011 Report Share Posted February 24, 2011 There are a lot of drivetrain related fans on all buses, the drivetrains are essentially the same in 40/60ft buses. I am not saying these NFs have hydraulic fans, but hydraulic fans are standard at most of the OEMs. For example NOVA LFS spec sheet - "Hydraulically driven cooling fans(2) - Standard". Scaling with the engine makes sense since the more load an engine has the more cooling it needs. If it does not need the cooling the fan isn't actuated. The fans in the back of buses are huge, so it is impractical to have a large electric motor to turn it (Electric cooled buses usually have 6 or 8 smaller fans on the radiator). Also the hydraulic fan never breaks, since it is really simple. That being said, it adds a lot more hose, which tend to rub into each other and burst, you can't change the fan direction to blow out leaves and dirt and if your power steering goes out, so does your fan. In short, hydraulic fans are still much cheaper to buy and operate and that's why they are on most buses. If there is a driver on this board that can go in the back of the bus and check we will know...large fan hydraulic, smaller fans electric. Fans powered by hydraulics? I'm skeptical about that that for 2 reasons: Firstly, a hydraulic system powering multiple components (there are a lot drivetrain-related fans on these artics) is inherently way more complicated and prone to mechanical failure than electric fans. This seems like a really weird engineering solution, especially in a drivetrain with robust electric capabilities. Secondly, in the 2nd video, the failed fan component (if that's what it is) spools up and down repeatedly during steady-state acceleration. If, as you say, hydraulic fans are dependent on engine speed, the offending fan would be producing its awful noise more steadily, since you can also hear that the engine is under steady load and RPM while accelerating and maintaining speed on LSD. And even if the engine RPM rose and fell during steady cruising (which doesn't seem to be the case in the video), it certainly wouldn't do so as much as that noisy fan seems to. Hydraulic fans that scale with engine speed are news to me. Doesn't mean there isn't a hydraulic component to their actuation, but I'd be really surprised if they were operated entirely with hydraulics AND scaled with engine speed. Quote Link to comment Share on other sites More sharing options...
sw4400 Posted February 24, 2011 Report Share Posted February 24, 2011 Another possibility which might be farfetched, that might be causing this noise. You got road salt all over the place. Maybe somehow road salt got into this area and is inhibiting whatever fan this is from working correctly. #4075 might've been one of the abandoned CTA buses on LSD during the blizzard of 2011. Quote Link to comment Share on other sites More sharing options...
busfan4022 Posted February 24, 2011 Author Report Share Posted February 24, 2011 I doubt thats the case, but it sounds plausible sw4400. Quote Link to comment Share on other sites More sharing options...
speedracer1407 Posted February 25, 2011 Report Share Posted February 25, 2011 There are a lot of drivetrain related fans on all buses, the drivetrains are essentially the same in 40/60ft buses. I am not saying these NFs have hydraulic fans, but hydraulic fans are standard at most of the OEMs. For example NOVA LFS spec sheet - "Hydraulically driven cooling fans(2) - Standard". Scaling with the engine makes sense since the more load an engine has the more cooling it needs. If it does not need the cooling the fan isn't actuated. The fans in the back of buses are huge, so it is impractical to have a large electric motor to turn it (Electric cooled buses usually have 6 or 8 smaller fans on the radiator). Also the hydraulic fan never breaks, since it is really simple. That being said, it adds a lot more hose, which tend to rub into each other and burst, you can't change the fan direction to blow out leaves and dirt and if your power steering goes out, so does your fan. In short, hydraulic fans are still much cheaper to buy and operate and that's why they are on most buses. If there is a driver on this board that can go in the back of the bus and check we will know...large fan hydraulic, smaller fans electric. I see what you're saying, OSUITS. I suppose it does make sense to have a simple hydraulic system powering a primary engine cooling fan, as they certainly are large and the plumbing is short. And the diesel engine in all of the CTA's NFs is the same cummins 10.8L ISM or 8.9L ISL. What I had in mind, however, is that the offending fan is not a primary engine cooling fan, but rather, one of the many fans associated with the electric drive/storage system. At this point, it's total speculation, as I'm not familiar with the specific architecture of the hybrid drive, but the offending fan in the video spools up and down independent of load and RPM. As the electric drive and storage system constantly shuttles electric power around the system, from the motors to the batteries, etc, it seems to make sense that this fan cools a component of that system, not diesel engine. These fans are likely much smaller, and since there's so many of them, it's unlikely they're all powered by a hydraulic system. Wouldn't it be great if there were a Cummins or NF engineer hanging around on this forum? Quote Link to comment Share on other sites More sharing options...
busfan4022 Posted February 28, 2011 Author Report Share Posted February 28, 2011 But you also have to take into consideration the volume of the noise the fan is making. I'm starting to think a small fan couldn't make that loud of a noise. It had to be something bigger than a small fan. Quote Link to comment Share on other sites More sharing options...
busfan4022 Posted May 20, 2011 Author Report Share Posted May 20, 2011 Interestingly, I just rode 4073 today and it was now experiencing the same problem. I haven't seen 4075 since the last time I've reported it, I'm not sure if it was moved to another garage or not. Quote Link to comment Share on other sites More sharing options...
Sam92 Posted June 20, 2011 Report Share Posted June 20, 2011 Interestingly, I just rode 4073 today and it was now experiencing the same problem. I haven't seen 4075 since the last time I've reported it, I'm not sure if it was moved to another garage or not. 4075 is back out. Rode it Saturday on the 14 Quote Link to comment Share on other sites More sharing options...
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