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Mind the Gap! Brightline's new bridge between the vestibule and train platform.

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Mind the Gap! Brightline's new bridge between the vestibule and train platform.
Posted by CMStPnP on Saturday, February 20, 2016 10:05 PM
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Posted by daveklepper on Sunday, February 21, 2016 3:15 AM

looks great!

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Posted by blue streak 1 on Sunday, February 21, 2016 7:08 AM

Mind the gap is apprpriate.  Many persons when going thru a door will turn immediately left or right especially if someone in front appears to be going slow..  How do you keep them going straight and not fall into a 12" gap ?

How wide are the New York subway gap fillers ?

Think idea great but are fillers wide enough ?

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Posted by ACY Tom on Sunday, February 21, 2016 11:38 AM

I have a few concerns.

 *  First, I wonder about the accumulation of snow. Would the mechanism be frozen in place? Would the mechanism be damaged by chipping with the "chisel" end of a snow broom?

*  Second, I wonder whether the mechanism would be damaged by the use of halite. Is it motorized? If so, that could present a reliability/maintenance problem.

*  Third, I wonder about use of the bridge against a curved platform. There might still be a gap at one corner or the other.

*  Fourth, I noticed that the bridge tilts down to match the platform.  Can it also tilt up if the track settles? Does this comply with ADA requirements for the vestibule level to match the platform level? I have long considered these ADA requirements to be impractical, but they do exist.

*  Fifth, I am concerned about the degree of "non-slipperiness" (is that a real word?) of the surface, especially when it is deployed with a slope, as shown.

*  Sixth, I agree that pushing and shoving could create a problem if the door is not monitored during boarding.  However, it appears that somebody is required to operate the bridge in the first place, and I would expect that a strict policy be mandated to keep that operator in place during boarding to maintain crowd control. If that isn't done, accidents could indeed happen. 

I hope nobody concludes that my concerns mean that I disapprove of the idea. It shows great promise. My concerns arise from many years of dealing with vestibule/platform safety issues.

Tom

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Posted by BaltACD on Sunday, February 21, 2016 12:09 PM

ACY

I have a few concerns.

 *  First, I wonder about the accumulation of snow. Would the mechanism be frozen in place? Would the mechanism be damaged by chipping with the "chisel" end of a snow broom?

*  Second, I wonder whether the mechanism would be damaged by the use of halite. Is it motorized? If so, that could present a reliability/maintenance problem.

*  Third, I wonder about use of the bridge against a curved platform. There might still be a gap at one corner or the other.

*  Fourth, I noticed that the bridge tilts down to match the platform.  Can it also tilt up if the track settles? Does this comply with ADA requirements for the vestibule level to match the platform level? I have long considered these ADA requirements to be impractical, but they do exist.

*  Fifth, I am concerned about the degree of "non-slipperiness" (is that a real word?) of the surface, especially when it is deployed with a slope, as shown.

*  Sixth, I agree that pushing and shoving could create a problem if the door is not monitored during boarding.  However, it appears that somebody is required to operate the bridge in the first place, and I would expect that a strict policy be mandated to keep that operator in place during boarding to maintain crowd control. If that isn't done, accidents could indeed happen. 

I hope nobody concludes that my concerns mean that I disapprove of the idea. It shows great promise. My concerns arise from many years of dealing with vestibule/platform safety issues.

Tom

Not to belittle items 1 & 2 - the system is proposed for the Brightline Florida route between Miami & Orlando - not too much snow accumulation in those areas.

All other concerns are more than valid.

Never too old to have a happy childhood!

              

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Posted by Wizlish on Sunday, February 21, 2016 1:40 PM

ACY
I have a few concerns.

 *  First, I wonder about the accumulation of snow. Would the mechanism be frozen in place? Would the mechanism be damaged by chipping with the "chisel" end of a snow broom?

As noted, there is likely to be little accumulation of ice and snow in Brightline's geographical area to 'jam' the system in the car (or to pile up on the platform edge; 'racking' the extruded bridge is likely to be one of the most critical failure modes and I will get back to that in a bit).  However, cold temperatures that might cause condensation ARE an issue, so 'freezing in place' might be a concern under some circumstances.  In any case, I agree that any 'volume' production of the car design should include optimization of the bridge design for the heaviest prospective ice and snow conditions (with lake-effect being one of the more onerous of them...)

Likeliest 'fix' for this would almost certainly be some kind of radiant or 'tracer' heating of the mechanism, perhaps combined with maintenance de-icing as used for aircraft leading edges.  I also suspect that some analogue of Airtabs could be provided to prevent snow accumulation on the car sides or sills that might build up (or melt) in a way that impaired the bridge deployment.

*  Second, I wonder whether the mechanism would be damaged by the use of halite. Is it motorized? If so, that could present a reliability/maintenance problem.

Valid concern, but I think Bode could do a detail design that was saltproof (for calcium chloride as well as rock salt).  Anodizing or powder-coating the bridge understructure, or using stainless steel of a kind that does not suffer chloride attack, might be approaches here; there are ways of lubricating the ways and providing protection for ball jackscrews or hydraulic rams that are either reasonably 'proof' against corrosion with sensible maintenance.

*  Third, I wonder about use of the bridge against a curved platform. There might still be a gap at one corner or the other.

The overlap would be substantial - probably several inches or more, at least enough to tolerate a car 'heeled' over on the secondary suspension.  The actual amount of 'curve' over the width of a doorway plus safety margins is not likely to be very great, and if it is, the system would be designed to have an additional inch or two worth of extension.  Even if there is a 'gap' it might be only a fraction of an inch, not enough for anything to drop through, and I don't think the 'Isadora Duncan' effect of a trailing scarf or whatever getting stuck in the wedge of an outside curve gap would actually hurt people or cause significant danger rather than just property damage.

*  Fourth, I noticed that the bridge tilts down to match the platform.  Can it also tilt up if the track settles? Does this comply with ADA requirements for the vestibule level to match the platform level? ...

This is an interesting question.  The answer, I think 'of course', is that the same mechanism that raises the dropped bridge could easily be arranged to raise it, but there may be insufficient space between the top of the bridge and the 'slot' in the sill to let the bridge articulate UP over the platform while it is still only partly extended.  A workaround for this is to have the bridge 'angled' (so it comes out at a rising angle, then drops or 'hinges' down to whatever final accommodation is), and then give it a double hinge so that there isn't a horizontal gap at the nose.

The other problem here is that the bridge needs to have structural thickness or depth.  When hinging down is the only function, there's no question that the 'tapered' nose of the bridge will be reasonably flat against the platform.  Hinging up would require an accommodation at the nose, probably using an elastomer of some kind rather than a mechanical hinge, to avoid a vertical gap or 'step' that might be outside ADA requirements.

These are things that I think the detail design of the Bode system can accommodate.

... I have long considered these ADA requirements to be impractical, but they do exist.

Do me a favor and go into detail about the specifics, and why you think it is impractical to realize them with an active ramp system.

*  Fifth, I am concerned about the degree of "non-slipperiness" (is that a real word?) of the surface, especially when it is deployed with a slope, as shown.

I am presuming that the ramp will have (as apparently pictured) anti-skid traction material with considerable 'tooth', probably crushed grit.  I also expect that the panel will be heated like the steps in that Russian trolley-car design so that any incident snow tracked onto it from a platform would not cause an extended slip/fall hazard, or persist and harden between stops into an ice hazard.

I do not think the slope angle is sufficiently large to pose a distinctive hazard greater than simply stepping across an 'equivalent' floor-to-platform height difference.  I don't know if it has been mentioned that the platform height of these 'gapped' platforms will have to be lower than 'Continental' platforms usually would be, by the height of the tallest part of the bridge as it is extruded;much of the 'tilt' being like that of special-accommodation rehab treadmills to provide the zero-walkover nose height for a bridge with actual structural strength. 

*  Sixth, I agree that pushing and shoving could create a problem if the door is not monitored during boarding.  However, it appears that somebody is required to operate the bridge in the first place, and I would expect that a strict policy be mandated to keep that operator in place during boarding to maintain crowd control. If that isn't done, accidents could indeed happen.

There is a rather obvious solution to this, which is pretty much common to transit projects in other areas: the use of 'platform doors' or even something as simple as portal frames at the door areas.  This controls access head-on to the gap, so the only remaining 'danger' is for a passenger to be pushed laterally between the car side and the portal frame into the gap.  There are ways to deal with this, too, ranging from extrudable barriers on the door or portal frames to the equivalent of 'telltale' fenders on the portal frames that a passing freight would push aside easily but even a stubborn passenger would not.

I suspect that even something as small as a paddle extruded from the train at waist height would catch most of the 'jostle' problem; surely there are cameras monitoring the doors even if attendants won't be at every one that has a bridge deployed, and while there are problems with safety systems that 'require' vigilance, it seems reasonable to me that most of the problems from 'pushing and shoving' could be identified by a conductor at the usual sort of central location in a consist, and appropriate action (like notification to specific door areas over a PA) taken before an accident has time to occur.

Briefly in addition:  The problem I see occurring at some point is that something hits or warps one of the bridges so it no longer tracks 'straight' as it goes to retract, and subsequently sticks or binds as it comes out.  At some point one of these things is going to extend when not over a platform and weight will come on it, perhaps offset to a corner (perhaps as something heavy rolls across it and then falls off in the shop).   This will produce at least the technical possibility of a non-ADA-compliant "fit" with the platform profile, or more significantly a train at a platform with a bridge that will not extend (which I think would keep that particular door 'soft-locked' closed) or one that will not retract (oodles and oodles of fun for everyone concerned!).

There is also the possibility -- I do not know how Bode interlocks the system, but there is a long history of this sort of failproof thing in aircraft design, like the lock on the DC-10 cargo door -- that a bridge will extend wholly or partly while the train is running, perhaps contacting something out of the loading gauge, or acting as a scythe to stuff it comes in contact with.  Presumably there is some reasonable 'breakaway' feature, but that has its own set of potential problems and issues.

My concerns arise from many years of dealing with vestibule/platform safety issues.

All the more reason to work the concerns out and attempt to address them early.

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Posted by ACY Tom on Sunday, February 21, 2016 5:08 PM

Regarding the ADA requirements for platform heights to match vestibule heights, I can't go into detail because I don't know the actual ADA specs. I do know that Amtrak has been required to make very significant and costly modifications to existing platforms in order to comply. In some cases, such as the very long platforms at the Auto Train facilities in Sanford FL and Lorton VA, the platform mods were required even though the mismatch was not great at all. In addition to the expense, these modifications necessitated serious operational disruptions and inconvenience to passengers and employees over a period of many, many months. My own personal opinion is that the cost and trouble was not justified by the very minimal improvement, which could be negated by future track settling.  But as I said, these ADA requirements do exist, practical or not.

Tom

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Posted by Wizlish on Sunday, February 21, 2016 7:13 PM

ACY
Regarding the ADA requirements for platform heights to match vestibule heights, I can't go into detail because I don't know the actual ADA specs.

I believe the current ADAAG is available here

https://www.access-board.gov/guidelines-and-standards/transportation/vehicles/adaag-for-transportation-vehicles

Subpart E is for commuter and transit railroads, subpart F for intercity passenger.  The specific section for commuter bridgeplates on cars starts with section 1192.95 

DOT ADA vehicle standards (and some other ADA material) are here:

http://www.fta.dot.gov/civilrights/12325_3884.html

Note that this also has links to the administrative history of the ADA with respect to transportation vehicles.

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Posted by CMStPnP on Sunday, February 21, 2016 7:31 PM

ACY

Regarding the ADA requirements for platform heights to match vestibule heights, I can't go into detail because I don't know the actual ADA specs. I do know that Amtrak has been required to make very significant and costly modifications to existing platforms in order to comply. In some cases, such as the very long platforms at the Auto Train facilities in Sanford FL and Lorton VA, the platform mods were required even though the mismatch was not great at all. In addition to the expense, these modifications necessitated serious operational disruptions and inconvenience to passengers and employees over a period of many, many months. My own personal opinion is that the cost and trouble was not justified by the very minimal improvement, which could be negated by future track settling.  But as I said, these ADA requirements do exist, practical or not.

Tom

So I am curious in your travels what the largest gap you have seen between the vestibule and the platform.    I seem to remember in the NE Corridor it's only a few inches at best a foot would be very rare.    Also noticed the new Amtrak ADA platforms only extend towards the train via a rubber ledge vs the whole platform down to the ground.    I think this bit of engineering is done in case the train does rock into the platform it just damages the platform slighly (if at all, since it is flexible rubber) instead of the train.

I think we are going to find with Brightline the gap is only a few inches because of more modern construction standards.    Also looks like the freight trains are going to avoid the platform aligned tracks as they pass through the rail stations on the line based on what I see on youtube videos.   Seems at each station they have a run around track for freight trains to continue to move around passenger trains.

I think you raise some good points though because I would bet that Amtrak buys the Simens cars if they prove to be popular and lower maintenance than the viewliners.     Interesting to note the first Cummins powered Diesel (Charger Model) for Midwest Corridor Service is already in Amtrak blue and Silver colors.

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Posted by MidlandMike on Sunday, February 21, 2016 9:05 PM

Swiss passenger trains have a similar door mounted gap filler that is automated.  I presume they have made provisions for freezing temperatures.

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Posted by daveklepper on Monday, February 22, 2016 4:07 AM

The question about New York City Subway gap-fillers, moving horizontally at curved station platforms:   Yes, they are considerably longer than the width of a subway car door.  This is, in part, to reduce the need for extremely precise stop positioning.  They are found only on ex-IRT stations.  (14th Street Union Square and the 42nd Street Shuttle, specific tracks. The old South Ferry and City Hall had them, too.)

On Jerusalem light rail, platforms, downtown being part of the sidewalks, match the car floor height within a millimeter or two and have a gap of about 30mm., 1.2 inches.  All platforms are on straight track.

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Posted by ACY Tom on Monday, February 22, 2016 9:31 PM

The widest gap I've ever seen was on a curve and it was probably less than a foot, although I never measured it, and can't recall precisely. 

Superliner cars have (or had) 2 small yellow bridge plates per car, designed for these situations. One was a long wheelchair ramp, and the other was a smaller folding step that attached to the door sill and extended about a foot or fifteen inches, and provided a small step about 6" down to the platform.   Both are fairly easy to use, except that the large ramp was fairly heavy and cumbersome for a small person to use. They were never a problem for me.

Tom

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Posted by Deggesty on Monday, February 22, 2016 9:45 PM

Tom, I wonder if the folding step you mention is on the Autotrain cars only, for I have never seen such on any Superliner I have ridden; all that I have seen is a step stool (lower, wider, and deeper than the stepboxes used with single level cars).

Johnny

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Posted by BaltACD on Monday, February 22, 2016 10:14 PM

CMStPnP

No guard railings to keep people from falling off the side and into the gap - as demonstrated in the video. 

Never too old to have a happy childhood!

              

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Posted by ACY Tom on Tuesday, February 23, 2016 10:46 AM

Deggesty:

I would be surprised if these items are only used on Auto Train cars. There is a designated storage location next to the P.A. box. After several Auto Train cars were damaged in the Crescent City derailment on April 18, 2002, I am sure they were on the cars sent as replacements to Florida from other trains. 

Those yellow Superliner ramps have a further advantage that I don't see on the new proposed design. They were designed for wheelchair use, and have a little lip on the edge to eliminate the possibility that a wheelchair wheel could go over the side.

Tom

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Posted by CMStPnP on Tuesday, February 23, 2016 12:28 PM

Airliners have these plates as well to bridge the gap between the extended walkway and the aircraft and they are a lot higher off the ground than the railway.    Have yet to see someone fall off one to the concrete 25-30 feet below.    At some airports in the United States the extended walkways do not always extend all the way to the plane.......depending on plane model.

The Gap is never big enough for a human to fall through at airports though.

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Posted by Wizlish on Tuesday, February 23, 2016 1:08 PM

Deggesty
Tom, I wonder if the folding step you mention is on the Autotrain cars only, for I have never seen such on any Superliner I have ridden; all that I have seen is a step stool (lower, wider, and deeper than the stepboxes used with single level cars).

Johnny, it isn't a step, it's a separate bridgeplate.  It's taken out of stowed location and laid across any gap, then picked up and put back.

There's enough difference from low Superliner doors to the platform height in Memphis that the easy-to-grab yellow stepboxes are commonly used.  I think there is more height difference than the ADA would permit for a ramp that could be easily stowed near an entrance, so I think there must be some other 'reasonable accommodation' provided to give low transition for a disabled passenger, perhaps a platform elevator at some point or a portable device that would raise and lower a transfer platform for a wheelchair user.  In my personal opinion, I suspect the bridgeplate would be used to make a 'ramp' and the car attendant would assist with wheeling or aided walking up or down -- but of course the language of the ADAAG appears not to permit this as an alternative for new construction.  Be interesting to see what happens when (not if!) one of those goofy test-the-law groups brings a class-action suit against Amtrak to implement full ADA-compliant access to all cars of the CONO in Memphis...

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Posted by Deggesty on Tuesday, February 23, 2016 2:44 PM

Yes, I have seen the rsmps that are stowed on Superliners--and I saw them used on the last trip my wife and took, for she was in a wheelchair. When we boarded in Jackson, Mississippi, the station personnel brought a lift out--and it took longer to get her on board using it than it would have if the ramp had been used.

Johnny

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