Rainforest
Senior Member
Depends on the acceptable acceleration .. if we assume 0.2 g (= 2 m/s^^2), then:
80 kph = 22.2 m/s, can be reached in 11.1 s
60 kph = 16.7 m/s, can be reached in 8.4 s
|
|
|
Depends on the acceptable acceleration .. if we assume 0.2 g (= 2 m/s^^2), then:
80 kph = 22.2 m/s, can be reached in 11.1 s
60 kph = 16.7 m/s, can be reached in 8.4 s
crs1026
Superstar
So, assuming the same rate of deceleration, and two stops 800 m apart....with no traffic light restrictions.....
80 km/h -
11.1 seconds to accelerate to top speed = 247m
13.8 seconds to travel 307 m at top speed
11.1 seconds to decelerate = 247m
Total - 36.0 seconds
60 km/h
8.4 seconds to accelerate to top speed - 140m
31.2 seconds to travel 520 m at top speed
8.4 seconds to decelerate - 140m
Total - 48.0 seconds
We are debating about 12 seconds per stop? The escalator to the subway level takes longer than that....
Please check my math
- Paul
Last edited:
Rainforest
Senior Member
I've rode TTC buses many thousand times, and TTC streetcars a few hundred times. Personally, I did not notice a huge difference in comfort.
The buses are usually warm enough in winter, and not too hot in summer. In terms of reliability, Queen and Dundas streetcar routes used to be worse than most of bus routes (not sure if this is still the case post-covid).
Reliability is independent on the vehicle type, it is greatly improved by dedicated lanes (which can be either LRT or BRT), otherwise depends on the active line management. Crowding can occur everywhere, I've been on crowded streetcars and subways countless times.
The only inherent advantage of a streetcar is a smoother ride, steel wheels vs rubber. But given that it costs a few billions to install a fully on-surface LRT on any long street - is the smooth ride alone worth the cost, or should a dedicated BRT for 1/3 of the cost be choosen.
Let's see what happens when Finch LRT is completed. I still hope it can operate at a decent speed (consistent with the early forecasts). If it does ~23 kph average, good enough. If it does 25, great.
But if it only manages 20 kph, or worse 18 kph just like the bus average - people will question whether a pair of BRT lanes was a better choice.
Edit: LRT must run faster than a mixed-traffic bus, because the LRT has 2 advantages by design: not sharing the lanes with cars, and having a wider stop spacing. So, if it LRT is not running faster, that doesn't necessarily mean LRT is a bad idea, but it certainly means the LRT operational practices have to be scrutinized.
Last edited:
Rainforest
Senior Member
I think that's correct. If the above scenario, ~ 60 kph top speed is sufficient, no much use going above that.
It would more useful to attempt a "smart" transit priority, that extends or shortens the transit phases in order to reduce the chance that the LRV has to wait at the traffic light.
zang
Senior Member
TTC bus drivers (IME) tend to be more considerate with the braking and acceleration. I've been (in very minor ways) hurt riding MiWay buses. Not sure what's up with that agency, but they put some real heavy-footed drivers behind the wheel. That includes on the TransitWay. If you like getting thrown around, MiWay's the way; bonus injuries if it's a flexi-bus.
Rainforest
Senior Member
I don't have any consistent experience with MiWay, only rode them a few times in my whole life. It is regretful if they are so careless.
I've been mostly on TTC, and sometimes on YRT. Both of them are not too bad in terms of acceleration. YRT drivers tend to be quite friendly, but their bus frequencies really suck.
evandyk
Senior Member
There's probably just more opportunity to get up to higher speeds on Mississauga's suburban streets than Toronto's more urban streets.
reinventingthewheel
Active Member
Train Travel Times Based on Distance, Top Speed, and Approx. Acceleration/Deceleration
Python Output:
Code:
Trip distance = d, top speed = v,
elapsed time = t
----------------------------------------
d: 400m, v: 50km/h, t = 39.73s
d: 400m, v: 60km/h, t = 37.12s
d: 400m, v: 80km/h, t = 35.49s
----------------------------------------
d: 600m, v: 50km/h, t = 54.13s
d: 600m, v: 60km/h, t = 49.12s
d: 600m, v: 80km/h, t = 44.49s
----------------------------------------
d: 800m, v: 50km/h, t = 68.53s
d: 800m, v: 60km/h, t = 61.12s
d: 800m, v: 80km/h, t = 53.49s
----------------------------------------
d: 1000m, v: 50km/h, t = 82.93s
d: 1000m, v: 60km/h, t = 73.12s
d: 1000m, v: 80km/h, t = 62.49s
Python:
# train travel times based on distance, top speed, approx accel and deceleration:
dists = [400, 600, 800, 1000] # m
v_kmh = [50, 60, 80] # km/h
v_ms = [v / 3.6 for v in v_kmh] # m/s
accel = 1.20 # m/s^2
decel = 1.35 # m/s^2
print("Trip distance = d, top speed = v,\nelapsed time = t")
for d in dists:
print("-" * 40)
for v_max in v_ms:
# ramp up and ramp down time (seconds)
ramp_up_t = v_max / accel
ramp_dn_t = v_max / decel
# ramp up and ramp down distance (metres)
ramp_up_d = v_max * ramp_up_t / 2
ramp_dn_d = v_max * ramp_dn_t / 2
# distance at max speed (metres)
v_max_d = d - ramp_up_d - ramp_dn_d
# time at max speed (seconds)
v_max_t = v_max_d / v_max
# elapsed time
t = ramp_up_t + v_max_t + ramp_dn_t
print("d: {:4}m, v: {}km/h, t = {:.2f}s " \
.format(d, int(v_max * 3.6), t))rbt
Senior Member
The operator probably prefers 80kph max. They can run ~2 to 3 fewer vehicles/drivers and maintain the same overall line capacity.
T3G
Senior Member
That's a trick question. Would the BRT be running with Novas, which might as well have no suspension for the level of comfort that they provide (which is zero) or something that is befitting a first world country?
Good old Orions.
drum118
Superstar
BRT vs LRT will always see BRT coming out cheaper than LRT on capital cost, but loose that advantage in operation cost and life cycle. It also loose on the quality of ride.
If BRT is running in mixed traffic or a traffic lane, it doesn't have to cover the cost to maintain the road as well being subject to rough road ride compare to an LRT that does the same thing, but pay full cost for that lane.
Do the math as to how many riders will be on the line per hour and divided that number by an articulated bus carrying capacity to see how many buses you will need. Then multiply that bus number by 3.5 that will represent the number of drivers. You need to see how many buses will be needed for a 30 year life cycle along with the cost to buy them.
As to doing the math for LRT, you need to do the same thing, but decide the length of the LRV to see how many you will need as step 1 to compare apples to apples. Step 2 will see if you can run one LRV or up to 3 as it mean a reduction in the number of drivers which happens to be the most expensive item for operation cost.
In a true comparison of apples to apples using a true ROW for both systems, LRT will be the winner over a 30 year life cycle that includes the construction cost. In a mixed cycle, the LRT still come out ahead, but not much.
Both system have the same issue when come to quality of ride beside smooth or rough rider and that is the driver. Some drivers are easy on the foot for starting and stopping while others are lead foot or on the throttle.
Building a true BRT will be faster than an LRT and how much depends on a number of things like the length and bridges to start with.
Seeing the Crosstown Line built as well the Finch Line, ION Line and Hurontario Line, each one was built different and to say which one is the better is throwing a dart at the wall. The same can be said for the Mississauga Transitway.
Until Crosstown, Finch and Hurontario lines are in service, it is pure guessing how they will run at the end of the day.
If BRT is running in mixed traffic or a traffic lane, it doesn't have to cover the cost to maintain the road as well being subject to rough road ride compare to an LRT that does the same thing, but pay full cost for that lane.
Do the math as to how many riders will be on the line per hour and divided that number by an articulated bus carrying capacity to see how many buses you will need. Then multiply that bus number by 3.5 that will represent the number of drivers. You need to see how many buses will be needed for a 30 year life cycle along with the cost to buy them.
As to doing the math for LRT, you need to do the same thing, but decide the length of the LRV to see how many you will need as step 1 to compare apples to apples. Step 2 will see if you can run one LRV or up to 3 as it mean a reduction in the number of drivers which happens to be the most expensive item for operation cost.
In a true comparison of apples to apples using a true ROW for both systems, LRT will be the winner over a 30 year life cycle that includes the construction cost. In a mixed cycle, the LRT still come out ahead, but not much.
Both system have the same issue when come to quality of ride beside smooth or rough rider and that is the driver. Some drivers are easy on the foot for starting and stopping while others are lead foot or on the throttle.
Building a true BRT will be faster than an LRT and how much depends on a number of things like the length and bridges to start with.
Seeing the Crosstown Line built as well the Finch Line, ION Line and Hurontario Line, each one was built different and to say which one is the better is throwing a dart at the wall. The same can be said for the Mississauga Transitway.
Until Crosstown, Finch and Hurontario lines are in service, it is pure guessing how they will run at the end of the day.
Natika33
Active Member
Your theory holds for me! I really dislike the TTC buses and avoid them as much as possible for every reason you mentioned. Conversely, I'll sometimes voluntarily opt to ride a streetcar over the faster subway when I have time, just so I can appreciate the view. Even though I have no car at present, I'd also choose the streetcar over driving even if it were a bit slower because it's far less stressful and I'm free to do other stuff like keeping up-to-date on Urban Toronto.
crs1026
Superstar
To be clear, I have no problem with riding seated on a bus, although I find the rear deck of a low floor transit bus to have questionnable legroom. But standee crush loading on a bus with the added constraint of large strollers or walkers in the front half, is misery, and often quite unstable.. TTC is no exception.
Subway can be just as bad at peak loading, the handholds are often unreachable Nd the geometry of a long reach is not always sufficient. Personally I find Flexities better riding than either.
- Paul
Subway can be just as bad at peak loading, the handholds are often unreachable Nd the geometry of a long reach is not always sufficient. Personally I find Flexities better riding than either.
- Paul
Natika33
Active Member
I have tailbone damage from sitting on a bus when it slammed into a pothole
T3G
Senior Member
I have tailbone damage from having to stand for 40 minutes on a crush loaded bus and trying my utmost to have as little of my body jutting out as possible!I have tailbone damage from sitting on a bus when it slammed into a pothole
Riding buses would be significantly more enjoyable from me if they had empty standee spots across from the rear doors like they did on the high floor buses. Standing on a rush hour bus, always in someone's way, I always feel like such an ass.