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Old 01-20-2014, 04:40 PM
 
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Originally Posted by nei View Post
I thought it counted as heavy rail, too. But checking wikipedia, heavy rail is a synonym for rapid rail transit.
Heavy rail isn't well-defined. It's usually just used as an antonym to light rail. Light rail isn't all that well defined either, but at least you know it when you see it :-).
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Old 01-20-2014, 07:30 PM
 
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Originally Posted by nei View Post
Also part of Boston's Blue line.
good point - all of the Blue Line, no?



Quote:
Generally, light rail is a local service with shorter stop spacing and higher frequencies. Compare, say Los Angeles light rail with its commuter rail. Or Philly's light rail with its commuter rail. I can't think of any commuter rail line with service every 15 minutes, except for shared lines close to the center city.
This is why light rail is so popular, because of its flexibility. Philly doesn't have any light rail within the city - just trolleys (or streetcars/trams if you prefer). The light rail that runs out to the 'burbs from 69th St. might have a few stations close together very close to 69th St. but they spread out as the route gets further out the stations get further apart.

A light rail network like Sacramento or Denver isn't that much different from SEPTA regional rail in terms of station spacing - it's just the SEPTA RR keeps going 40 miles out into the 'burbs to the edge of the exubrs so stations are sparse out there. That and SEPTA has closed a lot of stations over the last 30 years in an attempt to save money and speed up trip times. Still, the Chestnut Hill lines, the Media Line, Fox Chase, Wilmington (at least as far as Chester) has a very "light rail-esque" profile to the station spacing.

SEPTAs trunk line between University City and Jenkintown sees 15 minute service for most of the day.
NJTransit's NEC line varies but for most of the day it's no less than 30 minutes and usually more in the 10-20 minute range. LIRR routes like Hicksville see more service. If SEPTA had the money it could run every line every 15 minutes all day long. Aside from not having that kind of money it just doesn't fit the present ridership profile for most suburban areas.


Quote:
Metro North also use third rail within NY State.
I have noticed that before - and for the same reason as LIRR.


Quote:
First, to the user if the frequencies are similar the difference is small. And the trains can share tracks; as you said the NYC subway could run on LIRR tracks. In other parts of the world, it occasionally happens that the two systems use the same tracks for a bit. A few routes in London have that, it is the usual in Japan.
Right. If the frequencies are similar the difference are largely unimportant - assuming that the trip time is relatively small. I don't mind a 60 minute ride on CalTrain. I hate a 60 minute subway ride. That and it's far more expensive to run a SEPTA RR train or an LIRR train than it is to run light rail or a subway in Philly - if for no other reason than you're paying 3x the staff.

LIRR uses a 3rd rail (which is really not convenient but is more just a legacy thing) because it took a lot of older infrastructure when the RR was cobbled together. AFAIK, FRA regulations prohibit LIRR trains and MTA trains from sharing tracks. An LIRR would absolutely crush an MTA train in the event of a collision.

That's where the distinctions become important. As I said, what makes the modes different are the vehicles and the traction systems (although, as we've established, there are a few exceptions when it comes to traction). Light rail is the most flexible but you can't use existing main line tracks for it unless you get a FRA waiver and time-separate the uses. Metro rail, because of the 3rd rail, has to be completely grade separated or you have to spend a lot of money on fencing and special grade crossings (like LIRR) to mitigate the danger. It also keeps you from being able to use low level platforms.
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Old 01-20-2014, 08:08 PM
 
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Quote:
Originally Posted by drive carephilly View Post
LIRR uses a 3rd rail (which is really not convenient but is more just a legacy thing) because it took a lot of older infrastructure when the RR was cobbled together. AFAIK, FRA regulations prohibit LIRR trains and MTA trains from sharing tracks. An LIRR would absolutely crush an MTA train in the event of a collision.
The MTA subway (aside from the Staten Island Railway) isn't under FRA jurisdiction.
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Old 01-21-2014, 09:50 AM
 
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Coming into this late but I have always thought the difference between heavy rail and light rail was pretty straight forward.

Heavy Rail uses larger vehicles on a heavier track system. Generally it uses conventional rail the same as freight rail system uses. It often uses third rail to receive electrical power but can be diesel propelled. Commuter Rail systems such as MARC and VRC in the Washington DC area are heavy rail as is the Washington Metro and the Baltimore Metro (although the two Metro systems are not compatible). Heavy Rail systems are generally grade separated from other traffic and generally have the right of way over roadway traffic

Light rail uses generally smaller vehicles and the track used is generally lighter weight. Trolley systems such as the Baltimore Light Rail system and the proposed 'Purple Line' in the Maryland DC suburbs are light rail. They run generally on the surface often have to blend in with street traffic and have stop lights, etc. in urban areas (out in Suburban areas Baltimore's Light Rail does enjoy crossing gates and the ability to stop cross traffic to proceed through cross streets, etc.

Light Rail is cheaper because the track and substructure does not have to be built to handle the loads required of heavy rail. It would also be cheaper if grade separation is not required.
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Old 01-23-2014, 06:30 PM
 
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Originally Posted by nybbler View Post
The MTA subway (aside from the Staten Island Railway) isn't under FRA jurisdiction.

They still can't share tracks with commuter or freight trains - per FRA regs.
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Old 01-23-2014, 07:50 PM
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Location: Long Island / NYC
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Quote:
Originally Posted by drive carephilly View Post
They still can't share tracks with commuter or freight trains - per FRA regs.
true, though FRA regulations are unusual world-wide. Most countries didn't have anywhere near as stringent restrictions lighter trains sharing the tracks with heavier trains. US passenger trains are unusually heavy:

Bad FRA Regulations | Pedestrian Observations

As mentioned previously, small sections of the London Underground share tracks with mainline railways. The rapid transit can't share with commuter trains is an American peculiarity. Practically, they still usually don't as it makes scheduling harder.
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Old 01-23-2014, 08:42 PM
 
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Originally Posted by MidValleyDad View Post
Coming into this late but I have always thought the difference between heavy rail and light rail was pretty straight forward.

Heavy Rail uses larger vehicles on a heavier track system. Generally it uses conventional rail the same as freight rail system uses. It often uses third rail to receive electrical power but can be diesel propelled.
OK, now I throw in the Market-Frankford El (generally considered 'heavy') and the subway-surface system (not 'heavy') in Philadelphia, both of which are (the same) nonstandard gauge. And the Newark (NJ) city subway, which operates partially on a freight ROW.

The NJ River Line is even goofier, styled light rail and operating with diesel MUs on a former passenger line.
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Old 01-23-2014, 11:01 PM
 
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Originally Posted by nei View Post
true, though FRA regulations are unusual world-wide. Most countries didn't have anywhere near as stringent restrictions lighter trains sharing the tracks with heavier trains.
The FRA is rather strict but allowing light rail trains to use main line RR tracks is the worldwide exception not the rule.

Even when it is allowed the light rail trains have to meet the same safety standards - not the same FRA crash standards - but it's hardly as if it's common practice for light rail to share tracks with RRs. From what I've seen it's largely confined to Germany & the Netherlands.

I know that in Australia and Canada the rules are much the same as they are in the US.
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Old 01-25-2014, 12:08 AM
 
Location: BC Canada
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I thought this forum was about BRT?

You don't have to go to India or Latin America to find a large successful BRT system but rather just look north of the border.

The Ottawa Transitway has exclusive bus-ways {not just shoulders or HOV} for most of it's length and has very high ridership levels of approx. 200,000/day in a city of just 930,000. It is extremely fast, frequent, reliable, and the stations are real rapid transit stations and not just elaborate stops.

It covers every area of the city but it's biggest failure was the downtown core where the route merge into regular downtown streets and you can have "bunching" of up to 10 buses at a time crawling thru Ottawa downtown rush hour traffic. It is for this reason that the entire downtown/inner city section is being replaced with a downtown LRT tunnel.
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Old 01-26-2014, 05:25 AM
 
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Originally Posted by mooguy View Post
It covers every area of the city but it's biggest failure was the downtown core where the route merge into regular downtown streets and you can have "bunching" of up to 10 buses at a time crawling thru Ottawa downtown rush hour traffic. It is for this reason that the entire downtown/inner city section is being replaced with a downtown LRT tunnel.
Buses can also run in tunnels - but it's being converted to LRT because of crowding and because of the steep rise in operating costs associated with its popularity.

A 4 car light rail train can carry ~600 people. An articulated bus can carry ~120. With BRT you're paying 5 drivers to do the work of one LRT driver.
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