Comparing 
LRT and Subway Capacities 


Can LRT provide the same
capacity as Subway? No, it
cannot.
The Light
in LRT refers to its capacity, not to the weight of
vehicles or size of rail that it runs on. Naturally,
this means that it carries fewer people by definition.
But if it costs only a fifth to a quarter the price
to build, can we attain the same or greater capacity
spread over a wider area with two or three parallel
lines?
This
would not only save money, but allow for a less
costly expansion at a later date when added capacity
becomes necessary. At the same time, being ablet to
build parallel routes or an actual network
of routes leaves us with functional service when a
disruption occurs.



Capacity is number of passengers
per hour.
This
value is a product of two other values:
 How
many passengers fit comfortably on a vehicle?
 How
many vehicles can pass a given point in an
hour?
Number
of vehicles per hour is a product of two values:
 How many vehciles can be
coupled into a train?
 What is the minimum time
between trains?


How many passengers fit on a
vehicle?
Are
we going for a world record here? Images of clowns
spilling out of a car notwithstanding, there is a
figure called crush load that is sometimes used. This
is the absolute maximum number of passengers that may
fit on the vehicle  the worst case scenario. We are
not talking about that figure.
Specifications
for various vehicles will quote a value that
represents a comfortable maximum. The number of
seated passengers is simply the seat count on the
vehicle, and the number of standees represents a
comfortable maximum number of people standing. The
standee value is based on a maximum density, often in
the range of three people per square metre.




The chart to the left shows the
specifications of an HRV (the TTC's T1 Subway cars) and a
typical modern low floor LRV (the Siemens Combino Plus). The total capacity
of the HRV is 250, while the LRV is 184. To make
comparisons simpler, the rest of this page will use 250
for HRVs and will round down to 175 for LRVs.



How many passengers fit on
a train?
Subway:
1500
For
Subway, train length is primarily a function of
station length. For the TTC's Subway system, this
is six cars on the YUS and BD lines, but only
four cars for the Sheppard line (provision exists
to finish Sheppard stations to a full six car
length). For the compaison, six car trains will
be used for Subway.
LRT:
350525
The
flexibility of LRT allows it to operate in
tunnels, on an elevated structure, on a ground
level nonfenced right of way, in the median of a
road, or even in mixed traffic. To take advantage
of this full flexibility, station lengths can
become an issue when spacing between cross
streets become an issue. Newer generation LRVs
can have lengths in the 24 to 30 metre range. For
the most part, full flexibility can be achieved
by limiting train lengths to three cars (525
passengers). Transit City lines will likely only
use two car trains, for a capacity of 350.
Underground/isolated
LRT: up to 875
There
has been talk about revisiting a Downtown Relief
Line (DRL) in Toronto. Some of this talk has
suggested a southward extension of the Transit
City Don Mills LRT line. Given that this like
will arrive at Pape station on the BD Subway line
underground, such an extension is likely to also
be underground. In such an arrangement, station
size is not limited by city blocks or other
surface constraints. For the purpose of
comparison, the example of Edmonton will be used,
where underground LRT stations were built for a
maximum train length of five cars.



How many trains per hour?
Subway:
24 (up to 32 in the future)
Currently,
the TTC runs trains on a headway of about 150
seconds. That translates to 24 trains per hour.
Over the next decade, an upgrade to the
signalling system that includes Automatic Train
Control (ATC) will improve this. Some have
suggested 90 second headway possibilities, but it
is doubtful that this will be achieved. With all
trains turning back at the same terminals on a
line, the minimum practical headway is 140
seconds. With some trains shortturning, this
headway will be improved. This will occur when/if
the Spadina line is extended north of Steeles 
look at this document in the
paragraph titled Steeles West Station
if you don't believe what is written here.
Despite
these improvements, it is not likely that the
headways can be reduced below 110 seconds, or
about 32 trains per hour.
LRT:
15
It
has been suggested (see this article by Steve
Munro in the fourth paragraph under the title What
Can LRT Reasonably Carry?) that the
minimum spacing for onstreet operation (still in
a median ROW) is four minutes. This translates to
15 trains per hour. Anything below two minutes is
not practical due to traffic light timing, even
with transit priority.
Planning
for the Sheppard LRT line is looking at a minimum
headway of 5 minutes, which is 12 trains per hour.
Underground/isolated
LRT: 30
Closer
spacing can be easily obtained when not dealing
with surface traffic lights along the route. It
can easily be argued that 90 second headway is
possible in this situation, especially when we
are looking at some trains continuing on a line
at surface while some other trains turn back and
remain underground. For the purpose of this
analysis, a 2 minute headway will be used.



How many passengers per hour?
Subway:
36,000
24
trains per hour with 1500 passengers per train is
36,000 passengers per hour. If headways can be
brought down to 110 seconds, the figure increases
to 48,000. To compare with today's reality, the
Yonge Subway line currently carries about 40,000
passengers per hour during rush hour. These
passengers are packed in a little tighter than
the rating for comfortable standees, but
you probably already knew that!
LRT:
5,250 to 7,875
15
trains per hour with 525 passengers per train is
7,875 passengers per hour. Even with 2car trains
on this headway, the capacity is 5,250.
Underground/isolated
LRT: up to 26,250
30
trains per hour with 875 passengers per train is
26,250 passengers per hour. This figure is
assuming 5car trains with 2minute headways.
Even with 4car trains on a 3minute headway, the
capacity is 14,000.



North of Steeles: Less Frequent
Subway Service 

Note that the Spadina extension north
of Steeles will only carry every second train (and
perhaps only every third). For confirmation of this,
look at this document in the
paragraph titled Steeles West Station.
The same will have to occur on a Yonge extension in
order to increase capacity for the rest of the line.
This means that the capacity of these extensions will
be, at best, half of the normal capacity: 18,000 to
24,000 passengers per hour.
This is not a capacity issue, as there
will not be anywhere near this demand on either
extension.
What is does mean is that the frequency
of service will be half of what we are used to for
the rest of the line. For commuters, that means:
LRT from Steeles can provide the needed
capacity, and do so with shorter headways.


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This page last updated May 17, 2008
