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| (343401) | |
Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 08:12:36 2006 Why are train wheel axels solid? Having each wheel on a separate short axel, like a car, would save a great deal of friction and noise on curves. Of course coupling traction power to the wheels would be a bit more dificult, but not byond today's engineering possibilites. Then there are many trailing cars - all freight and many passanger service - where traction to all wheels is not an issue? |
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Re: Wheel Axels |
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Posted by Train Dude on Sun Nov 26 08:57:42 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. "Having each wheel on a separate short axel, like a car, would save a great deal of friction and noise on curves."I disagree with your hypothesis - especially the part about friction. What do you base this conclusion on? |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 09:35:06 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. Since wheels are tapered the wheels do not have much friction, in curves the wheel on outside runs on bigger taper, the inside wheel runs at smmaller taper. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 09:39:13 2006, in response to Re: Wheel Axels, posted by Train Dude on Sun Nov 26 08:57:42 2006. Going around a sharp curve the outside wheel must rotate more rapidly than the inside one in order to not slip (friction). This cannot happen with a solid axel. Of course train designs over more than a century have tried to cope with this by using the tapered flange on the wheel. This works ok, but just ok. Going with a split axel would allow the inner and outer wheel on a curve to rotate at whatever rate they need. No screetching on a tight curve. Eg. South Ferry. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 09:40:49 2006, in response to Re: Wheel Axels, posted by Dutchrailnut on Sun Nov 26 09:35:06 2006. Yes, I know, Dutch Man. But, I am wondering; wouldn't a split axel work better? |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 09:52:26 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 09:40:49 2006. nope it would cost twice in maintenace of bearings and if the Talgo is example it is disatrous during derailments. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 10:07:30 2006, in response to Re: Wheel Axels, posted by Dutchrailnut on Sun Nov 26 09:52:26 2006. I'm sure it would cost more; you're right.What is Talgo? |
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Re: Wheel Axels |
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Posted by Terrapin Station on Sun Nov 26 10:18:48 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 10:07:30 2006. This is talgo |
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Re: Wheel Axels |
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Posted by Subterranean Railway on Sun Nov 26 11:22:32 2006, in response to Re: Wheel Axels, posted by Train Dude on Sun Nov 26 08:57:42 2006. Try driving a rear-wheel drive car without a differential. Each wheel rotates at a different speed when turning. If the wheels were forced to rotate at the same speed, there'd naturally be more kinetic friction between the wheels and the ground. |
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Re: Wheel Axels |
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Posted by Subterranean Railway on Sun Nov 26 11:24:28 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. Of course coupling traction power to the wheels would be a bit more dificultCouldn't this be accomplished by coupling a motor oriented perpendicular to the truck to a differential? After all, that's how rear-wheel drive works... I believe that rubber-wheeled trucks have separate axles for each wheel, since the friction coefficient between rubber and steel is much greater, and the wheels' taper is nonexistent. |
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Re: Wheel Axels |
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Posted by Broadway Lion on Sun Nov 26 11:37:48 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 09:39:13 2006.   Going around a sharp curve the outside wheel must rotate more rapidly than the inside one in order to not slip (friction). This cannot happen with a solid axel. But you are wrong, and that is exactly what they do. But Railway wheels are not flat from inside to outside. They have a taper from the flange to the inside. The outside diameter by the flange is much greater than the inside diameter of the wheel. On tangent (straight) track, the flange is no where near the railheads. The train can go for miles and miles, and the flange will never touch the rail. But when the train goes around the curve, the outside wheel rides closer to the flange, and the inside wheel rides closer to the axle. This differential is what allows a solid wheelset to negotiate the curves without slipping or friction. When the (N) train goes around the corner at Canal Street, the high pitched squeal you hear is the flange rubbing against the railhead. They used to squirt grease in there to reduce that friction and noise, but nowadays railroads use water for this purpose, which is cheaper, more environmentally friendly, and is not tracked all over the wayside. ROAR [Now the LION will look to see what other replies you have gotten.] |
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Re: Wheel Axels |
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Posted by Sand Box John on Sun Nov 26 12:16:59 2006, in response to Re: Wheel Axels, posted by Subterranean Railway on Sun Nov 26 11:24:28 2006. Couldn't this be accomplished by coupling a motor oriented perpendicular to the truck to a differential? After all, that's how rear-wheel drive works...I believe that rubber-wheeled trucks have separate axles for each wheel, since the friction coefficient between rubber and steel is much greater, and the wheels' taper is nonexistent. You also have the extra weight of the quill that encloses the two half’s of the axle and the differential. Two words “cost benefit”. As Dutchrailnut said, “. . . it would cost twice in maintenance of bearings . . .” add to that the higher up front cost to manufacture and assemble all the parts compared to the existing wheel sets. I thought of this more then 30 years ago, after analyzing it for a while I concluded that the benefit wasn’t worth the higher capitol and maintenance costs. John in the sand box of Maryland's eastern shore. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 14:17:58 2006, in response to Re: Wheel Axels, posted by Broadway Lion on Sun Nov 26 11:37:48 2006. Had the Lion looked at other responses first he'd have noticed that this writer is well aware of the theory and use of the tapered wheel flange. All he is asking is wouldn't split axels be better. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 14:19:18 2006, in response to Re: Wheel Axels, posted by Subterranean Railway on Sun Nov 26 11:22:32 2006. Absolutely correst. So, why not build trains that way too? THAT was my question originally. |
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Re: Wheel Axels |
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Posted by Fulton Frank on Sun Nov 26 14:21:09 2006, in response to Re: Wheel Axels, posted by Sand Box John on Sun Nov 26 12:16:59 2006. OK good answer. Still it would be fun to build a proto type and see how much more quietly it rounds tight curves. |
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Re: Wheel Axels |
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Posted by tracksionmotor on Sun Nov 26 14:38:26 2006, in response to Re: Wheel Axels, posted by Broadway Lion on Sun Nov 26 11:37:48 2006. Well, I haven't seen water in use for years on NYCTA. They still use 'greasers' which CLICK a SQUIRT under hydraulic pressure. When you do undercar even on 'New Tech' you must be careful when inspecting wheels because there is always a wad of grease waitng for your elbow. Subways operate tight curves.... every wheel inspection requires the use of a thin flange/high flange gauge NYCTA # 210A (if I remember correctly) which is basically go/no go. RRCI Peter |
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Re: Wheel Axels |
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Posted by tracksionmotor on Sun Nov 26 15:22:23 2006, in response to Re: Wheel Axels, posted by Train Dude on Sun Nov 26 08:57:42 2006. TD: Fulton Frank is semi-correct IF he is thinking along the lines of part -time 4WD where both wheels are locked through a transfer case with vehicle driving on dry pavement...the inside wheel turns faster than outside wheel causing excessive tire wear and strain on transfer case....but we're talking trainzzzzz!Basic trainset truck has a solid axle with a fixed gear ratio to tractionmotor which never changes (I'm answering Frank) that offers ultimate reliability. Consider weight and kinetic energy required to move a trainset from a standing start....all of the stress would be placed upon the differential gears which would fail. Far simpler to accept some additional wheel wear...subways don't run high speeds, long distances and most track surfaces have wear to the point of being 'polished.' The one exception is the Bombardier R-142s. The design of the truck is supported above the axles with hard rubber chevrons that allow the axles to 'twist' following a curve hence 'steerable trucks.' On normal railroad trackage, this is an excellent mechanical situation...the wheels still don't spin at different rates BUT results in a smoother ride avoiding flange contact with rail. Problem was that NYCTA has extensive curves and automatic brake adjusters of Tread Brake Units attempted to compensate for what was worn brakes on outside wheels resulting in burned brakes and more. 'TBU-A Program' changed out over 7000 brake units sucessfully. I show my guys wheels and traxxx. The surface profile of a track is a curve. Wheel profile is such that the trainset settles in between the track...the flange never touches the rail and it is there as a safety device. I use a flashlight and a piece of paper to show normal contact between wheel and track is 1/10th of an inch or so. Sorry TD for using your posting for reflection. IF I could only post..........but I cannot....and I'm sure you know why by now! RRCI Peter |
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Re: Wheel Axels |
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Posted by tracksionmotor on Sun Nov 26 15:36:34 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 14:21:09 2006. In rail, it is not a matter of 'quietness' but proper transfer of energy from wheel to rail with minimal friction and maximum adherense. The size of a differential to be inserted in a 2400 pound + wheel/axle assembly would be humoungous. In the 1920's, somebody got an idea that a variable gear transmission in steam engines would allow for maximum transfer of power by shifting gears.Short lived...even todays most technologically advanced 'green trainsets' use fixed axles and gear ratios. RRCI Peter |
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Re: Wheel Axels |
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Posted by Bill West on Sun Nov 26 15:45:34 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. Look at the right angle gear case on an RDC truck, it’s huge, just under the diameter of the wheels. A differential would cost as much as a traction motor to buy and maintain. More importantly, as the noise is the flanges and not the tread taper/difference in wheel turning radius a split axle wouldn’t help anyway.Also I have the impression that although solid axles are semi mass produced a long history went into learning how to forge them properly and that the production batch tests are very tough. They are the size they are because the load and fatigue on them is that high. So a split design would have to be fairly big. And as axles don’t seem to fail for less than a few million per incident I doubt if any one would easily want to rock the boat with a new concept. Bill |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 15:50:41 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 14:19:18 2006. With a differencial the traction motor during slip would only power one wheel and other would do nada.with a solid axle the traction motor will keep driving both wheels. |
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Re: Wheel Axels |
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Posted by Broadway Lion on Sun Nov 26 16:32:22 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 14:17:58 2006. Wildebeests are better than split axles. You can eat wildebeests, even if axles do have more Iron in them.ROAR |
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Re: Wheel Axels |
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Posted by metropod on Sun Nov 26 16:40:21 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. I don't mean to go OT, but there are self propeld frieght cars. The Cooperstown & Charolte Valley Railraod used to own a self propled coal hopper (they traded it for a ballest tamper) |
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Re: Wheel Axels |
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Posted by WillD on Sun Nov 26 17:57:50 2006, in response to Re: Wheel Axels, posted by Dutchrailnut on Sun Nov 26 09:52:26 2006. Pardon? I haven't heard of any 'disasterous' Talgo derailments outside of one in Cartuja, Spain and a fairly minor one involving the Amtrak Cascade Talgos at Portland caused by a faulty switch. What bearing would a solid axle have during an accident? I believe the issue you're debating is the lightweight construction of the Talgos, which have nonetheless proven themselves robust enough for the US market. The Talgos may have twice as many bearings to maintain as say an Amfleet, Superliner, or Surfliners, but somehow they maintain the highest availability of any Amtrak passenger equipment. |
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Re: Wheel Axels |
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Posted by WillD on Sun Nov 26 18:34:41 2006, in response to Re: Wheel Axels, posted by Subterranean Railway on Sun Nov 26 11:24:28 2006. You just described the propulsion layout on a PCC II LRV :)I apologize for the quality of the photo, it was taken with a crappy P&S digital camera from the inspection bay at Elmwood Depot, but it should show things well enough. The large, roughly hex or octagonal housing in the upper left corner is the differential. From that one the upper right you can see the axle to the rear wheel. Going down the picture from the differential you see the brake disc, needed only for the last few MPH since the asynchronous motor, located immediately behind the disc, handles most braking through regenerative or dynamic braking. On the right, behind the rear axle is the motor for the front axle, the brake disc, and the differential, arranged in mirror to the rear axle's powertrain.  I should say that I don't know whether the differentials are fixed or not. I know engine braking is possible through a differential, so the fact that all braking outside the electric track brakes (visible as the black bar with silver dots on it in the photo) goes through the differential should not be a major problem. It is entirely possible that Kiepe outdid themselves and installed a limited slip differential or something similar in the PCC IIs, or they simply have a gearbox in there which converts the longitudinal axis torque from the motor into a transverse axis torque for a fixed axle. At the time I was underbody I never thought to ask anyone what the case was. However, it isn't absolutely neccesary to have one motor supply both wheels through an LSD. The GG1 used one motor for each of its twelve driven wheels. If a modern locomotive, DMU or EMU were to borrow the GG1's approach and use between eight and twelve AC asynchronous motors of lower power than the current four to six motors on most locomotives yet retain the traction control and other features you could have each wheel powered exactly as needed, responding to the conditions immediately at the railhead/wheel interface, and probably always at zero speed relative to the rail. This could have tremendous benefits for things like wheelslip and resulting wheelflats, as well as reliability. Admittedly it could increase the workload on the motor shop, but it would also probably make that work somewhat easier since it'd be smaller motors. |
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Re: Wheel Axels |
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Posted by tracksionmotor on Sun Nov 26 18:58:54 2006, in response to Re: Wheel Axels, posted by Fulton Frank on Sun Nov 26 14:17:58 2006. Cut me a #239 NF 36" from American tool steel please. Wheel flanges are not tapered...they have a definite profile set by AAR which I inspect with AAR profile gauges. minimum width must be 14/16th of an inch and flange height is 17/16th inch. Upon inspection, I mark axles in chalk with tread thickness, flange correction and flange height...notifying wheel defects marked on wheel directly and indicating in in my inspection reports per FRA requirements.Railroad work is dangerous work. Observe Safety Rules, wear your PPEs and raise the Blue Flag. STAY SAFE. RRCI Peter |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 19:47:56 2006, in response to Re: Wheel Axels, posted by WillD on Sun Nov 26 17:57:50 2006. With the single wheel on axle the worst bearing for maintenance is on inside. since wheels are taperd the inside bearing needs to be a dual bearing, both for load and as trust bearing since axle wants to go to insde due to wheel taper.With a solid axle the axle carries the inward trust of both wheels. And since every wheel needs to be replaced once it travels x amount of feet of the rail it becomes a maintenance headache. |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 19:50:49 2006, in response to Re: Wheel Axels, posted by WillD on Sun Nov 26 18:34:41 2006. A diffencial it is not, its a angled drive.on differential the planetary gear feds two half axles. On PCC the axle is solid with a angled gear and bull gear from drive shaft |
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Re: Wheel Axels |
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Posted by Dutchrailnut on Sun Nov 26 19:52:31 2006, in response to Re: Wheel Axels, posted by tracksionmotor on Sun Nov 26 18:58:54 2006. The wheel is tapered with a secondary flange transitioning into main flange. |
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Re: Wheel Axels |
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Posted by nasadowsk on Sun Nov 26 20:18:17 2006, in response to Re: Wheel Axels, posted by WillD on Sun Nov 26 17:57:50 2006. Pardon? I haven't heard of any 'disasterous' Talgo derailments outside of one in Cartuja, Spain and a fairly minor one involving the Amtrak Cascade Talgos at Portland caused by a faulty switch.There haven't been any. DRN's blowing smoke out his ass, as usual. The simple fact is there's nothing wrong with independent wheels, and the design issues are well known and manageable (and not unique to Talgos anyway). The Talgos have them, most low floor equipment has them, and they've been around for years. On top of which, the Talgo design is claimed to be free from the hunting motions that plague other designs, and truck hunting is very dangerous at high speeds. If they were dangerous, it'd have appeared decades ago. On top of the above, the design also means much shorter axles, which has advantages too, plus you have two bearings carrying each wheel's load. Maintenance? They're famous for availability. The biggest 'problem' people have with Talos is they don't look like a normal train. Big whoop. |
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Re: Wheel Axels |
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Posted by Sand Box John on Sun Nov 26 20:26:59 2006, in response to Re: Wheel Axels, posted by WillD on Sun Nov 26 18:34:41 2006. The GG1 used one motor for each of its twelve driven wheels.The motor pairs on a GG-1 were geared to a quill surrounding the axel that transferred rotational force directly to the two wheels pressed onto common axel through a flexible connection. The individual wheels on a GG-1 were not independently driven and would not roll independently. John in the sand box of Maryland's eastern shore. |
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Re: Wheel Axels |
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Posted by BIE on Sun Nov 26 20:34:58 2006, in response to Re: Wheel Axels, posted by Sand Box John on Sun Nov 26 20:26:59 2006. John, you sre correct. WillD would be fascinated by the way the spider quill transmitted it's torque to rubber blocks which were attached to the driver spokes on the GG-1. |
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Re: Wheel Axels |
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Posted by Sand Box John on Sun Nov 26 21:15:34 2006, in response to Re: Wheel Axels, posted by BIE on Sun Nov 26 20:34:58 2006. John, you sre correct. WillD would be fascinated by the way the spider quill transmitted it's torque to rubber blocks which were attached to the driver spokes on the GG-1.The twin motor gear quell drives used on the GG-1 is illustrated in William D. Middleton "When The Steam Railroads Electrified" both additions in Appendix B "The motive power of electrification". A friend of mine worked as a hostler at Ivy City back in the late 1970s early 1980s. I remember a time when he cracked the throttle of a GG-1 when I was standing on the ground with engine breaks applied. I watched the flexible connection compressed after hearing a clunk as torque was applied to wheels John in the sand box of Maryland's eastern shore. |
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Re: Wheel Axels |
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Posted by VictorM on Sun Nov 26 21:21:31 2006, in response to Re: Wheel Axels, posted by BIE on Sun Nov 26 20:34:58 2006. I thought they used coil springs mounted circumferentially between the wheel spokes to connect the quill to wheel. I know they did it that way on the New Haven EP-4 electrics. |
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Re: Wheel Axels |
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Posted by Train Dude on Sun Nov 26 21:25:59 2006, in response to Re: Wheel Axels, posted by tracksionmotor on Sun Nov 26 14:38:26 2006. No - it's either a 230 gauge or a 231 gauge depending on where you work. |
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Re: Wheel Axels |
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Posted by BIE on Sun Nov 26 21:46:29 2006, in response to Re: Wheel Axels, posted by Sand Box John on Sun Nov 26 21:15:34 2006. i don't need an illustration. Our local NRHS chapter has a GG-1 |
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Re: Wheel Axels |
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Posted by BIE on Sun Nov 26 21:46:57 2006, in response to Re: Wheel Axels, posted by VictorM on Sun Nov 26 21:21:31 2006. Rubber |
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Re: Wheel Axels |
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Posted by Train Dude on Sun Nov 26 21:49:19 2006, in response to Re: Wheel Axels, posted by Subterranean Railway on Sun Nov 26 11:22:32 2006. Absolutely incorrect. Comparing railway wheels to the rear axle of a car shows a total lack of uderstanding of the subject. However, why would you ask for people's opinion if you only want validation of your idea? If that's all you want - okay, you are correct - a split axle would be better. There, does that make you feel better? |
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Re: Wheel Axels |
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Posted by Subterranean Railway on Sun Nov 26 21:56:36 2006, in response to Re: Wheel Axels, posted by Train Dude on Sun Nov 26 21:49:19 2006. Why were you so offended by my post? I never asked for others' opinions, nor did I want validation of my idea. You needn't adopt such a snide attitude.Why is it incorrect to compare the rear wheels of a car to railway wheels? |
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Re: Wheel Axels |
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Posted by Sand Box John on Sun Nov 26 21:58:49 2006, in response to Re: Wheel Axels, posted by BIE on Sun Nov 26 21:46:29 2006. i don't need an illustration. Our local NRHS chapter has a GG-1The GG-1 owned by your local NRHS chapter may not be as easily accessible to all that read this forum as a copy of Middleton’s book would be. John in the sand box of Maryland's eastern shore. |
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Re: Wheel Axels |
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Posted by Sand Box John on Sun Nov 26 22:09:36 2006, in response to Re: Wheel Axels, posted by VictorM on Sun Nov 26 21:21:31 2006. BIE is correct, rubber. See illustration in William D. Middleton "When The Steam Railroads Electrified" both additions in Appendix B "The motive power of electrification" The GG-1 gear quill drive with the rubber torque block is illustrated without wheels and axel.John in the sand box of Maryland's eastern shore. |
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Re: Wheel Axels |
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Posted by Train Dude on Sun Nov 26 22:56:28 2006, in response to Re: Wheel Axels, posted by Subterranean Railway on Sun Nov 26 21:56:36 2006. First of all, I was not offended other than your dismissal of my point with your comment of try driving a rear wheel car. I've driven many rear wheel drive cars in my day. There is no comparrison.First of all, rubber tires are flat whereas rail wheels are tapered. The taper is deliberate to take into account just the problems that you suggest exists. Second, the solid axle adds structural integrity to the truck frame. If the lateral stresses of independently mounted wheels were factored in, the truck frame would need to be made heavier and stronger to account for the stressed that the current axle/wheel assembly endure. Third, having a solid axle aids in control and reduces maintenance. Since wheels are pressed onto the axle at about 105 tons of force, it's unlikely that they will rotate independently of one another. In other words, if one wheel is turning, it's opposite wheel is turning. This will reduce the frequency of flats or grooved treads due to locked wheels. In addition, where we now need 4 slip-slide units per car, your idea would mandate 8. |
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Re: Wheel Axels |
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Posted by 19characterusername on Sun Nov 26 23:36:01 2006, in response to Re: Wheel Axels, posted by tracksionmotor on Sun Nov 26 15:36:34 2006. Yeah, with electric propulsion and fancy voltage and frequency control of AC induction motors the motor and controller effectively act as a CVT. Series hybrids have fixed gearing for the same reason.That being said I've been on a Scottish DMU that sounded like it had a two speed transmission. I believe it was a 150 series Metro-Cammel DMU Sprinter. Before that I didn't know that people put mechanical linkages between prime movers and axles on rail vehicles since steam pistons. |
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Re: Wheel Axels |
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Posted by nasadowsk on Mon Nov 27 00:06:09 2006, in response to Re: Wheel Axels, posted by 19characterusername on Sun Nov 26 23:36:01 2006. Some DMUs have mechanical transmissions, or hydromechanical types. You also sometimes hear a 'gear changing' noise on electrics, but that's just the VFD changing carrier frequencies as needed. Some types do, some don't, and it's not an IGBT vs GTO thing, since IGBT types do it too. More like what the engineers writting the software felt like :)I don't mind VFD carrier noise, but the constant shifting drives me nuts. I've yet to ride a PCCII, but they sound awfully like an ABB industrial inverter - just white noise. |
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Re: Wheel Axels |
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Posted by Olog-hai on Mon Nov 27 00:30:45 2006, in response to Re: Wheel Axels, posted by nasadowsk on Sun Nov 26 20:18:17 2006. The biggest 'problem' people have with Talgos is they don't look like a normal trainWhat does a normal train look like? No, the biggest problem with Talgos is that they can't stop at high platforms and thereby can't run in the Northeast—you sure won't be able to get an ADA-compliant version. (Talgo cars show a mere six feet above a high platform—six feet!) |
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Re: Wheel Axels |
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Posted by Jeff H. on Mon Nov 27 02:45:28 2006, in response to Wheel Axels, posted by Fulton Frank on Sun Nov 26 08:12:36 2006. It would be a maintenance nightmare for very little gain inperformance. 1) You would need to introduce a differential with planetary gears. 1A) You know what happens when one wheel of an automotive differential slips: the other wheel loses torque. Would you introduce a limited- slip differential? Imagine how expensive and troublesome that would be considering the torque involved. 2) Having the wheels pressed solidly onto a rigid axle serves another important point that nobody mentioned yet: track geometry. If the axle were split, how would you maintain the wheelset gauge? All that lateral force would be on the thrust bearings of the differential. PCC cars have right-angle hypoid drive which looks like an automotive differential but it is a solid axle and no planetary gears. |
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Re: Wheel Axles |
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Posted by Bill West on Mon Nov 27 04:04:01 2006, in response to Re: Wheel Axels, posted by WillD on Sun Nov 26 18:34:41 2006. Huge difference in G's per axle horsepower compared to a PCC II.Bill |
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Re: Wheel Axles |
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Posted by Bill West on Mon Nov 27 04:05:49 2006, in response to Re: Wheel Axels, posted by VictorM on Sun Nov 26 21:21:31 2006. History has coil springs around each pin, coil springs between the pins and the spokes and rubber designs.Bill |
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Re: Wheel Axels |
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Posted by BIE on Mon Nov 27 09:52:12 2006, in response to Re: Wheel Axels, posted by Sand Box John on Sun Nov 26 21:58:49 2006. True enough. |
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Re: Wheel Axels |
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Posted by Jace on Mon Nov 27 10:10:03 2006, in response to Re: Wheel Axels, posted by Olog-hai on Mon Nov 27 00:30:45 2006. The other problem with Talgos is getting them to meet FRA Tier 1 structural requirements - do you put collision posts on every car or on the one on each end of the trainset? The trains in service now came in before the regulations changed. |
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Re: Wheel Axels |
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Posted by Jace on Mon Nov 27 10:15:41 2006, in response to Re: Wheel Axels, posted by tracksionmotor on Sun Nov 26 15:22:23 2006. The R142 trucks are not true steerable trucks - the chevrons, like the radius arm bushings on the Kawasaki trucks, provide some degree of movement. In both cases, you want the rubber stiff enough so that the wheels don't move about at speed on tangent track yet offer some flexibility when attacking curves so that the wheels don't wear out in a few thousand miles. It's a delicate balance. |
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