For a SAFEGE monorail, the trains ride suspended beneath the track. The wheels/suspension/brakes/etc. ride inside of the box-beam track, while the cabins are suspended below, connected to the wheels, etc. through a continuous slot at the bottom of the track/beam. The top of the track goes basically unused. Why not make use of that space for a bike path?
I can think of two reasons. First, with a narrow, lightly-loaded structure (with no filing cabinets, bookshelves, etc.) that spans long distances between supports, vibrations can be an intractable problem. The rhythmic nature of walking or jogging can produce uncomfortable and even dangerous oscillations through resonance. This problem can be solved by strictly restricting access to the bikeway. Absolutely no pedestrians, skateboarders, or rollerbladers. (This will make cyclists ecstatically happy.)
The second issue that needs to be addressed is the geometry. Monorail tracks are too narrow for a useful bikeway, even SAFEGE tracks, which are wider than other types of monorail tracks. A SAFEGE monorail track might be only four or five feet wide; a useful bikepath needs to be at least ten or twelve feet wide. The solution is not to simply scale up a SAFEGE track to make it wide enough for a bikeway. That would be an inefficient use of material and would also likely make the tracks too heavy to easily lift into place. A better solution would be to build the tracks as a composite T-beam. The rectangular steel monorail track could be kept small and light (and easy to install), designed not to be able to resist the weight of fully loaded monorail cars and eight feet of snow, but only strong enough to support the weight of a 12-foot wide concrete slab that would be poured into place after the steel has been lifted into position. Once the concrete sets, it will make the composite section much stronger--strong enough to support the weight of the monorail trains and the hordes of new bicycle commuters.
Once this system is built, it could be the seed that leads to the construction of paron's Bicycle Skyway.
I agree
No opinion
I disagree
Add your comment
Great idea...but naturally any bicyclist would like it. I would go with some type of perpetual wind-at-your-back system (a.k.a. cyclists nirvana). Divide the bike subway vertically at the center, add some roof wind scoops to take advantage of favorable wind and some power assisted fans to get cyclists to 20 mph…max. The energy to ride at 20 mph with a 15 mph breeze at your back (57 watts) is a fraction of 25 (447 watts) or even 20 mph (245 watts) – see http://www.kreuzotter.de/english/espeed.htm. Additionally, it will be easier to talk on the cell, sip the latte, read the newspaper and put on makeup at 20 with that tail wind.
Also, check out http://www.biketrans.com/ for a similarly great idea.
First reason this does not work: You need elevators every kilometer so people can get up on the monorail. Who will pay for electricity and maintenance? Yes you could build ramps for bicyclists. But it's a hassle to go up ramps with a bike so nobody would use the system.
#2: How do you want to prevent people from walking up there? Why would a bike cause less vibration than somebody walking anyway?
It's so much easier to build bike roads where they belong: at ground level.Uncool? Yes. Cheap? Yes. Tested and tried? Of course.
The beauty of this idea is its low pricetag. An elevated bicycle skyway for just the cost of some railings and an extra floor to service for the elevators at each station. The rest of the required infrastructure is built as part of the monorail system. A lot of extra functionality for just a little extra cost.
The bicycle skyway would only be accessible at stations, and the combination of turnstiles and station managers would serve to prevent non-paying cyclists and pedestrians from accessing the skyway. It is important to preclude pedestrians because of the rhythmic nature of foot travel- the periodic impact of foot hitting pavement can cause disturbing, even dangerous, vibrations through resonance. People automatically, subconsciously tune their stride to match the natural frequency of the surface they tread upon. This saves energy and effort for the pedestrian, but it is the worst possible situation for the underlying structure. (It is to avoid this problem that marching soldiers are required to break step when crossing a bridge.) Wheeled transport does not excite structures' vibrational modes in the same manner, so while the elevated tracks of a monorail would not be suitable for a pedestrian walkway, bicycles are easily accomodated.
Regarding elevation: My first thought was "just have the bikeway BENEATH the trains" (this is done on the East Side of the San Francisco Bay -- there's a bike path beneath the BART tracks), but then I figured that there are probably cars down there -- which is exactly why we would benefit from the elevated path. If a bicyclist has to choose between hauling his bike up some stairs and riding among car traffic, he will generally choose to haul his bike up stairs.
Regarding vibrations: wouldn't the train passing underneath create considerable vibrations?
The overall concept is good, but wind shear and torsion from changing weight distributions will likely be major factors in an engineering study. There are much lighter weight materials than concrete for building the structures you propose. And in the not too distant future, nanotubes may provide cardboard-thin surfaces stronger than 6 inches of concrete, a fraction of the weight, and contributing strongly to the overall structures strength.
I like the fact that the bikeway is only accessible at stations -- keeping them far enough apart helps make them unattractive to pedestrians. If is is a half-mile walk between stations, and you're at the station anyway, just buy a ticket and get on the train, right?
Don't most stations have an elevator? I don't mind (much) horsing a bike up the stairs, but I'd sooner not.
Providing bike storage at the bikeway elevation would be a partial solution. You could ride from home to your destination station, leave the bike up there, walk to where ever, come back, go up to bikeway level, and ride home. No bike-on-stairs. Sometimes, of course, it would be worthwhile to negotiate the stairs, but not usually.
I love this idea. I invision it like this:on top, the monorail with bike trail on top, monobikes, underneath the monorail train, right? So, why can't we have a walk/jog trail underneath all that on the ground? navigating either around the support pillars or through arches. I'd like to see this endeavor taken on by my community.