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#411
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Stephen Sprunk wrote:
On 29-Jan-12 17:57, Adam H. Kerman wrote: Stephen Sprunk wrote: On 29-Jan-12 14:09, wrote: On Jan 29, 11:07 am, Stephen Sprunk wrote: Movement of tanks. That is the origin of the clearance, lane width and bridge-strength requirements--and in turn limits the height, width and weight of new US tanks. I'm not sure that's true. Tanks are not very kind to concrete roadway surfaces, nor do they move very fast, and of course drink up fuel. I would think if tanks have to be moved any sort of distance they would be loaded onto trains. The tanks would not be directly on the roadway unless they were actually deployed for battle on US soil, in which case I doubt anyone would care about what it did to the pavement. Otherwise, the tanks would be on transporters, which is why the Interstate vertical clearance requirements are so high. Transport is designed to current standards, not the other way around. The "standards" of the day varied significantly from state to state and were, in many places, completely insufficient for the Army's needs. The entire purpose of the Interstate system was to unify and raise those standards _to match the transport needs_. Here in Chicago, which may have more elevated railroads than anywhere else, the required elevation standard was based on trucks of that era. Why would any state have had lower vertical clearance standards than required for trucks of that era? Can you tell us what the hell state you are talking about that wouldn't have had standard clearances for bridges being built for trucks currently being sold? Were there any significant number of trucks sold that exceeded 12' 6", a common vertical height limit prior to 1956? Expressways in my area prior to 1956 didn't have 13' 6" clearances until they were reconstructed. btw, you are wrong: To this day there is no FEDERAL vertical height standard on trucks. That's in state law. There are federal standards on length, width, and weight of trucks. I found that on truckinfo.net. Don't consult Wikipedia, which merely ripped off that Web site. In theory, the Army _could_ have tried to redesign their tanks, etc. to the size, height and weight of a Model T or horse-drawn wagon--what much of the US road infrastructure of the day could handle--but they probably wouldn't have fared too well in battle. Now you're moving the goal posts from vertical clearance to weight that bridges can support. Of course bridges in rural areas were designed for the vehicles that would cross them typically, straight-bodied trucks that farmers might own. The concept that roads and bridges would be designed for trucks that don't exist is awfully odd. |
#412
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On 30-Jan-12 17:37, Robert Bonomi wrote:
*HOWEVER*, tanks are *heavy* -- substantially surpassing the legal load limits on most highways. An "M1A1", alone, NOT INCLUDING the weight of the transporter vehicle, is close to double the legal weight limit on most highways. Load limits are specified per axle or tandem, and tank transporters have _lots_ of axles to spread the tank's weight out. Also, the load limits are based on civilian traffic at high speed for decades. It is well known that such limits can be exceeded at lower speeds for short periods--such as a military convoy. (The current tank transporters are only rated for 45mph, ironically slower than modern tanks can move on their own.) They are also _big_. TWELVE ft wide. (needless to say, that doesn't fit 'in' a standard traffic lane, with any safety margin ![]() .... and the standard traffic lane is exactly twelve feet wide. However, the transporter is _not_ that wide; a tank hangs off both sides, possibly over one shoulder or the other if the transporter is not perfectly centered in the lane. There are standard shoulder widths, too: ten feet on the left and twelve feet on the right. However, they're not required to support the same weight as the main lanes--which is fine since neither tanks nor transporters should be driving on them. Eight ft tall -- not including any antennas -- _before_ considering the height of the transporter. (a flat- bed type trailer will have a bed level that is approximately 5' above ground.) Isn't the standard minimum bridge height 14ft6in? Hint: that's just slightly taller than a tank or APC on a transporter. S -- Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking |
#413
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#414
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Stephen Sprunk wrote:
Isn't the standard minimum bridge height 14ft6in? Hint: that's just slightly taller than a tank or APC on a transporter. The standard bridge height is the height limit for trucks in that state, plus six inches, which allows for a layer or two of asphalt being added to the surface of a concrete highway. |
#415
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#416
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In article ,
Stephen Sprunk wrote: On 30-Jan-12 17:37, Robert Bonomi wrote: *HOWEVER*, tanks are *heavy* -- substantially surpassing the legal load limits on most highways. An "M1A1", alone, NOT INCLUDING the weight of the transporter vehicle, is close to double the legal weight limit on most highways. Load limits are specified per axle or tandem, and tank transporters have _lots_ of axles to spread the tank's weight out. Some are, some are *not*. 'More axles' doesn't make any difference to a bridge span. grin. (The current tank transporters are only rated for 45mph, ironically slower than modern tanks can move on their own.) Yup. ... and the standard traffic lane is exactly twelve feet wide. However, the transporter is _not_ that wide; a tank hangs off both sides, possibly over one shoulder or the other if the transporter is not perfectly centered in the lane. Oh my. We're having an agreement. grin Tanks are "oversize", and "overweight" loads, and, under 'non warfare' conditions, aren't moved on public roads without special permits, markings, and escort vehicles. The transporters are built to be 'street legal' when unloaded, so that they -can- use the highways without all that hoorah. Eight ft tall -- not including any antennas -- _before_ considering the height of the transporter. (a flat- bed type trailer will have a bed level that is approximately 5' above ground.) Isn't the standard minimum bridge height 14ft6in? Hint: that's just slightly taller than a tank or APC on a transporter. In the U.S., placarded if less than 13' 6", I believe. Max legal height for vehicles w/o requiring 'oversize vehicle' permits and routing approval. 'Roofline' height for a, say, M1A1, on a transporter would be a bit over 13'. Aux. 'fixtures', can add another 1+ ft. Yup. right close to Defense highway clearance requirements. |
#417
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In article ,
"Adam H. Kerman" wrote: I don't know what a transit system would do if it simply sold unlimited ride passes with no credit bank to debit from. Does anyone know of an example? In Chicago, one type of CTA Cubic fare media, Chicago Card Plus, can be used for both single trips and monthly passes. It's linked to a credit card. The monthly pass is applied to the card after debiting the fee from the credit bank, and can also be used at the same time to pay the single fare for accompanying passengers, although just one pass can be encoded on it at a time. The ORCA card in use in the Puget Sound area does not necessarily have to be linked to a credit card. Cards that do not have a registered owner can only be recharged from a vending machine or transit agency office rather than through the web site. As far as I know, it is possible to put a monthly pass of various types* on the card at these vending machines using cash or credit card, but in either case the machine supposedly only uses the card information for conducting the single transaction. * There are some seven agencies, with a single route on an 8th, that use the card as a possible fare media. Thus, the need for various agencies to be able to load their type of monthly pass onto the card. -- Please note this e-mail address is a pit of spam due to e-mail address harvesters on Usenet. Response time to e-mail sent here is slow. |
#418
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In message , at
21:46:42 on Mon, 30 Jan 2012, Glen Labah remarked: I don't know what a transit system would do if it simply sold unlimited ride passes with no credit bank to debit from. Does anyone know of an example? In Chicago, one type of CTA Cubic fare media, Chicago Card Plus, can be used for both single trips and monthly passes. It's linked to a credit card. The monthly pass is applied to the card after debiting the fee from the credit bank, and can also be used at the same time to pay the single fare for accompanying passengers, although just one pass can be encoded on it at a time. The ORCA card in use in the Puget Sound area does not necessarily have to be linked to a credit card. Cards that do not have a registered owner can only be recharged from a vending machine or transit agency office rather than through the web site. The same is true of London's Oyster, although more recently they have added an "auto-topup" facility when the stored credit falls below £8. I've also got a bus smartcard, which simply has stored credit measured in "days" (and can only be topped up at a particular travel centre), where I can have unlimited travel on any day that I use it. But I don't have to use it every day (like I would a conventional season ticket, which are of course widely available for train and bus on smartcard). In some cities that would be called a carnet (of day-tickets). http://www.nctx.co.uk/nct-fares/easy...ider-citycard- anytime-adult/ I don't buy it for the discount, as much as not having to find the exact change to ride on the bus when paying the driver. -- Roland Perry |
#419
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"Adam H. Kerman" wrote:
I don't know what a transit system would do if it simply sold unlimited ride passes with no credit bank to debit from. Does anyone know of an example? The ORCA card in use in the Puget Sound area does not necessarily have to be linked to a credit card. Same with the Clipper card used in the San Francisco area. A card can have both passes and a cash balance for trips not covered by any of the passes. It works on seven different transit systems and can handle a baffling array of passes and discount plans. You can have a Muni monthly pass, and a BART High Value Discount ticket which gives you $64 of BART credit for $60, as well as passes on other systems and cash. Each agency's vending machines tend to sell its own pass as well as loading cash. Same with the PATH Smartlink card. You can add a daily, weekly, or monthly pass for cash at vending machines. There are doubtless others, but those are the ones I happen to have here. R's, John |
#420
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John Levine wrote:
Same with the Clipper card used in the San Francisco area. *A card can have both passes and a cash balance for trips not covered by any of the passes. *It works on seven different transit systems and can handle a baffling array of passes and discount plans. *You can have a Muni monthly pass, and a BART High Value Discount ticket which gives you $64 of BART credit for $60, as well as passes on other systems and cash. Is BART credit stored separately from otehr agencies' credit? In the NYC region, the 7% Metrocard bonus when you load at least $10 applies to the credit you can use on any agency that takes Metrocard. I'm not sure how they "fund" the bonus. (Consider that a card could have been loaded multiple times, sometimes with the bonus and sometimes without, so it's hard to figure out how much real cash revenue the card balance represents.) Jimmy |
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