Sunday, 13 November 2011

Some Tech Talk

Just to answer a few questions that have been sent to me:

Why don't they put winter tires on slinky buses so they don't get stuck all the time?

Winter tires wouldn't work, not even with chains, to provide the kind of traction needed to keep artic's rolling when the snow gets deep. The problem is not about tire contact. The problem is articulation on a rear drive vehicle. 

Lock the turntable, the bus will move. The turntables on these buses are all hydraulics anyway, build a brake within the turntable to lock it in place when the traction control is activated, and you will solve most of the issues with the bus running off track as the trailer pushes the center axle any direction but forward. 

It's a pretty simple manufacturer-based solution to a pretty simple problem.

With gas being so expensive, why do you guys run your buses all the time?

Here's the official policy on idling:
i. Temperatures below  -5˚C (degrees Celsius) – Do not shut the bus off. All 
buses are to be kept running to avoid start-up problems. Bus operator is to 
place the transmission in neutral, apply the Spring/Parking Brake and let the 
bus idle on “Fast Idle”
Please Note: All buses are to have the “fast idle” switch in the „ON‟ position when idling. 
If the switch is in the on position when the bus is parked, the switch may need to be 
toggled off and back on to activate the fast idle, as the default is low idle regardless of 
switch position.
ii. Temperatures above -5˚C (degrees Celsius) – All bus engines are to be shut 
down when lay-up is expected to exceed seven minutes, as follows:
Observe a three minute high idle shut-down procedure – let the bus idle, 
in neutral, with the “fast idle” switch in the „ON‟ position, for three minutes 
before shutting down the engine
Observe a three minute high idle start-up procedure – let the bus idle, in 
neutral, with the “fast idle” switch in the „ON‟ position, for three minutes 
before departure.

Saving fuel isn't really built into the idling procedure. Somebody up top has been convinced that buses are better to idle for a minimum of 6 minutes each time it stops, and scheduling rarely provides for more than 6 or 7 minutes between runs.

If the company really wants to save fuel, reducing the number of stops along many routes would be a good start. the 131/27 route has an average stop spacing of 200 meters along a 2 km stretch. Some of the stops are located less than 20 meters past stop signs at intersections. Why stop a bus at a stop sign or traffic light, then have it stop 20 meters later to pick up or drop off passengers? Stopping and starting is the single most fuel thirsty activity you can do in a bus. Reduce the stops by locating flags where the bus has to stop anyway, and add up the hundreds of times the bus wont stop there in a day, you will save fuel. Now "optimize" the number of flag stops along routes. I bet you could reduce fuel use significantly through better planning.

More questions? Just ask!

2 comments:

  1. I have a question!

    I've seen bus drivers send in Status 6's when they're too full to accept more passengers. What other statuses are there?

    ReplyDelete
  2. The biggest problem is that the whole system is built for convenience rather than efficiency. It's completely impractical in many respects.

    ReplyDelete