## Carfree concept mapping with Google Earth

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• I just recently downloaded Google Earth and have spent quite a bit of time looking at the satellite pics of places I used to live, work, and go to classes. As
Message 1 of 3 , Jul 21, 2006
time looking at the satellite pics of places I used to live, work, and
go to classes.

As I was looking at all these places, I started thinking in my mind
about how these places could be converted to carfree areas without
having to demolish any existing buildings or even take any private
property. Obviously, property owners in the area will convert their
parking lots into green space--or most likely, will sell their parking
lots to a developer or develop over the parking lots themselves.

I want to put some of these maps online with notations showing my
ideas of converting to carfree areas. First, some questions--namely
for Joel, but anyone could answer them:

- To cut-and-cover a heavy-rail, two-track metro on an existing
street, how much width is required for the tracks? How much width and
length do we need for a station? What is the minimum turn radius for
heavy-rail metro?

- Same thing for on-street light rail. Track width? Track plus

- Just a quick check, but would the readers here prefer I use feet or
meters? I might be in the USA, but I'm comfortable either way. ;-)

I used to live in a three-story, 35-unit apartment building with
commercial within walking distance, and I feel that the area around it
would be ideal to a carfree development, assuming that there was
enough public spine to actually do it.

I currently live in a two-story, three-unit apartment building, again
with commercial within walking distance. For reasons of personal
privacy, I won't be doing carfree concept mappings for where I live
now. :-)

Thanks

matt
• ... Obviously clearances vary depending on width and length of rolling stock and whether there are masts for overhead electrification. Here in the UK, the
Message 2 of 3 , Jul 22, 2006
Matt Hohmeister wrote:

> <snip>
> - To cut-and-cover a heavy-rail, two-track metro on an existing
> street, how much width is required for the tracks?

Obviously clearances vary depending on width and length of rolling stock and
whether there are masts for overhead electrification. Here in the UK, the
usual minimum width of straight, double-track, standard-gauge lines in
tunnels and between overbridge abutments and viaduct parapets is 26' (8m).
I'd say 26-30' (8-9m) minimum.

> How much width and length do we need for a station?

By convention, the length of a station is a bit more than the length of the
longest train that stops there. Sorry for not being more specific! :-)
Width depends on how many passengers use the station, but minimum of 8'
(2.5m) for side platforms, more for island platforms.

> What is the minimum turn radius for heavy-rail metro?

The traditional unit of length for UK railways (and roads) is the chain (22
yards or 66 feet). This is a very useful length because one chain is almost
exactly 20 metres.

Usual minimum radii for heavy rail in the UK are 7.5-10 chains (495-660' /
150-200m).

> Same thing for on-street light rail. Track width?

A single-track, standard-gauge light rail line fits comfortably in a 12'
(3.65m) traffic lane.

> Track plus platform width?

See above.