Wizlish zkr123 I'm not talking about light rail, I was talking about heavy rail. The height from the first step of a comet/Amfleet to a lot of low level platforms is pretty significant. I was wondering if a kneeling bus like technology could help make it easier to board and leave the trains. The 'straight' answer is no, even for a modified Amfleet car that would have very long secondary springing on the bolsters. But the actual idea is not quite so dumb if we think outside the box about 'kneeling'. What actually needs to 'kneel' (i.e. be depressed against a permanent spring 'suspension' by an air cylinder or gearmotor arrangement) is just the part of the vestibule where the steps are... not the whole end of the car. You can't 'drop' the whole vestibule end down because of the center sill and draft gear, but one side can easily be pulled down, say, on roller chains, so the bottom step is at 'ground level' or even well below rail level, eliminating the need for a stepbox (which was the original point, I think). This in essence gives you one more (temporary) step" at the top, between the trap and the center corridor in the vestibule (with the other side trap surface acting as a 'landing') to lengthen the stair flight to the ground. The kind of 'roll-out' steps seen in pictures of early streamlined equipment might work, too (when deployed they might even project beyond clearance, giving additional steps at relatively low individual stepover height). (It would also be possible to provide certain cars with the equivalent of a wheelchair lift instead of steps at one 'corner' -- similar in operation to the devices used to move wheelchairs up and down stairs. This would move the trap and safety rails outboard slightly and then down tracks arranged past the edges of the steps, with a linkage holding the platform horizontal until it is close to the ground. It might then be tipped, or a roll-out ramp extended (as on a bus) to give quick zero walkover height. There's probably too much liability involved with a device that standing passengers would be riding vertically -- but you might be able to provide something like a folding safety seat (or wheelchair) that locks into place just for the trip...
zkr123 I'm not talking about light rail, I was talking about heavy rail. The height from the first step of a comet/Amfleet to a lot of low level platforms is pretty significant. I was wondering if a kneeling bus like technology could help make it easier to board and leave the trains.
The 'straight' answer is no, even for a modified Amfleet car that would have very long secondary springing on the bolsters. But the actual idea is not quite so dumb if we think outside the box about 'kneeling'.
What actually needs to 'kneel' (i.e. be depressed against a permanent spring 'suspension' by an air cylinder or gearmotor arrangement) is just the part of the vestibule where the steps are... not the whole end of the car. You can't 'drop' the whole vestibule end down because of the center sill and draft gear, but one side can easily be pulled down, say, on roller chains, so the bottom step is at 'ground level' or even well below rail level, eliminating the need for a stepbox (which was the original point, I think). This in essence gives you one more (temporary) step" at the top, between the trap and the center corridor in the vestibule (with the other side trap surface acting as a 'landing') to lengthen the stair flight to the ground.
The kind of 'roll-out' steps seen in pictures of early streamlined equipment might work, too (when deployed they might even project beyond clearance, giving additional steps at relatively low individual stepover height).
(It would also be possible to provide certain cars with the equivalent of a wheelchair lift instead of steps at one 'corner' -- similar in operation to the devices used to move wheelchairs up and down stairs. This would move the trap and safety rails outboard slightly and then down tracks arranged past the edges of the steps, with a linkage holding the platform horizontal until it is close to the ground. It might then be tipped, or a roll-out ramp extended (as on a bus) to give quick zero walkover height. There's probably too much liability involved with a device that standing passengers would be riding vertically -- but you might be able to provide something like a folding safety seat (or wheelchair) that locks into place just for the trip...
Don't forget US passenger equipment uses tightlock, interlocking couplers which endeavor to keep all cars in the same horizontal plane. To lower the vestibule end of one car, it would also lower the end of the adjoining car it was coupled to, this could be a problem unless cars were coupled at the vesitbule end and both cars were lowered as a unit.
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zkr123I'm not talking about light rail, I was talking about heavy rail. The height from the first step of a comet/Amfleet to a lot of low level platforms is pretty significant. I was wondering if a kneeling bus like technology could help make it easier to board and leave the trains.
I accept that criticism that perhaps I should have been a lot more gentle in my criticism. The point though is that some check on feasibility should be performed, some thoughfulnes, and I hope we can learn.
Did you ever see a kneeling bus that could not get back up and had to discharge its passengers and wait for a repair truck? I saw one once. Anybody else see one or was on one?
And yet the amount of kneel isn't all that great. My experience is that the drivers use the feature only for handicapped and elderly.
The first day of trials of Jerusalem light rail wI was surprised by the narrow clearance between door sills and platforms, just about like an elevator. And it works without a problem.
To me, the OP was unaware of the details of the construction of the cars that he thought could be modified so that it would be easier for passengers to board them. My first thought upon reading the original post was, "It can't be done." I appreciate the explanations as to why it cannot be done (or would be extemely difficult to do) by men who are far more familiar with the details of construction than I am. Considering the apparent lack of knowledge of construction on the part of the OP, I would not want to say that it is a stupid idea.
Johnny
Every idea that pops into one's head should be checked for some feasibiltiy before posting it. Don;t you notice that when a bus "kneels" it also moves sl;ightly sideways? And tha the front door goes down, but the rear of the bus actualloy moves up a bit? An automobile is a thing unto itself, it doesn't need to react with rails and other cars in a train.
I really say, there has never been a posting as stupid as this one. If someone can name one, please do.
zkr123 Yes I have ridden of tram/light rail service but I'm not talking about light rail, I was talking about heavy rail. The height from the first step of a comet/amfleet to a lot of low level platforms is pretty significant. I was wondering if a kneeling bus like technology could help make it easier to board and leave the trains.
Yes I have ridden of tram/light rail service but I'm not talking about light rail, I was talking about heavy rail. The height from the first step of a comet/amfleet to a lot of low level platforms is pretty significant. I was wondering if a kneeling bus like technology could help make it easier to board and leave the trains.
Look at the trucks of a full size, heavy rail commuter car and you can see the engineering problems with your idea.
Some type of retractable ramp on the platform might be more feasible (though maybe not much more practical)..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
That's why the conductor or trainman will put out a stepbox. At any rate, the subsequent steps in the vestibule are still of a pretty good size due to space limitations.
Has the questioner ever ridden a modern streetcar or light rail system with low-floor cars? These cars have level boarding fourteen inches above railhead, which is only slightly higher than a normal sidewalk above vehicle road paving. This is a perfected reliable technolgy. Admittadly such cars are more expensive to build and maintain than equivalent high-floor cars, three feet to fifty inches above railhead and meeting equal-height high platforms, but not nearly more expensive than adding some addition up and down movement to the cars. In other words, the added investment in kneeling is unnecessary, would simply add other complications, and makes in truth as much sense as addding a steering wheel. Yeh, why not have drivers of light railcars control the direction at switches by use of a bus-type steering wheel? This question is equally nonsensical.
Or why don't buses have rudders? And gangpanks? Trains too. How about safety vests and life presevers in case a bus goes off the road or a train derails on a bridge?
CSSHEGEWISCHIt wouldn't work since a kneeling bus involves an adjustment to the suspension system which lowers the frame and body
I think a distinction has to be made between 'conventional' equipment and inherently low-floor transit equipment.
For conventional heavy rail, the situation is largely as indicated. Keep in mind that the suspension situation is a bit different between bus and rail. The kneeling-bus system doesn't work by 'lowering the suspension' the way low-riders do it -- a failure would make the bus rapidly unsafe or put it out of service. Instead, it jacks DOWN the conventional suspension. On a railroad car, there isn't enough compliance in the primary suspension (on the trucks) to get more than a few inches' worth of drop, and the secondary suspension not much more. (Peripheral note: on a bus, the 'primary suspension' is the rubber tires, and you may note that nobody proposes kneeling the bus by deflating/inflating the tires!)
There's little point in making the 'bottom step' low-walkover if there is still so much step-up to the car floor that you need steps or long ramps. Also as indicated, you would have to 'drop' the whole train, not just one car.
On a low-floor transit car, the kneeling situation is potentially more attractive, especially if the couplers between cars can be designed to accommodate drop and twist. The question is the extent to which true zero walkover height is required. I suspect much of the same effect could be achieved with extendable powered ramps much more easily than with changes in already-expensive low-floor trucks and drive equipment.
Even if you collapsed the suspension on a railcar, you'd only lower it a few inches. Not sure that really helps accomplish anything useful.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
It wouldn't work since a kneeling bus involves an adjustment to the suspension system which lowers the frame and body. Lowering the frame in a passenger car for something similar would be difficult to impossible because of tension in the couplers and frame if the slack is run out or the interlocking function in tightlock couplers if the slack is bunched.
Has anyone ever considered using the leaning/kneeling bus technology on single level rail cars? Especially ones like amfleet or comet/horizon which are also designed to work on high level platforms.
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