ION - Waterloo Region's Light Rail Transit

[Canard]

I keep forgetting to mention it, but the traffic lights (and presumably, the railway crossing lights and arms) at Courtland & Siebert are now activated.

I think that would signal (ha!) the last true bit of construction of the original scope of the project being completed.

[KevinL]

Indeed! Good to know.

We still need the Traynor walkway crossing to Fairway, but that wasn't in the original scope.

[Canard]

Train testing has resumed! 502, 508, and 513, at the very least, are out. Operation on the full alignment (Conestoga to Fairway) today.

Edit - Oops, 513 is going back to the OMSF, the gong just stopped working. LRV swap! It'll be either 510 or 514 coming out, instead.

[Canard]

Train testing continues today.

[tomh009]

We were in downtown Toronto on boxing day. Yesterday, as I was walking in DTK to work, 508 went by, from Charles to Benton/Frederick, to Duke. What struck me was how much quieter it was going around the turns than the (new) Toronto streetcars. Is this all down to the track lubricators? Do the streetcar systems not use those?

[ijmorlan]

We were in downtown Toronto on boxing day. Yesterday, as I was walking in DTK to work, 508 went by, from Charles to Benton/Frederick, to Duke. What struck me was how much quieter it was going around the turns than the (new) Toronto streetcars. Is this all down to the track lubricators? Do the streetcar systems not use those?

I don’t think they have the grease lubricators, but I’m not sure about that. Don’t forget, they have tighter curve radii on many turns, which is another difference.

[danbrotherston]

We were in downtown Toronto on boxing day. Yesterday, as I was walking in DTK to work, 508 went by, from Charles to Benton/Frederick, to Duke. What struck me was how much quieter it was going around the turns than the (new) Toronto streetcars. Is this all down to the track lubricators? Do the streetcar systems not use those?

I don’t think they have the grease lubricators, but I’m not sure about that. Don’t forget, they have tighter curve radii on many turns, which is another difference.

I think but am not sure that TTC also has turns which aren't spirals, which may contribute to noise and the occasionally jarring ride.

[Canard]

Dan’s hit the nail on the head.

The TTC’s old network has fixed-radius curves, without transition spirals, which are less suitable for fixed-bogie trams. The CLRV and ALRV’s have no issue because the steerable bogies take care of the body lead-in and lead-out. Sit in the back seat of the new TTC Flexities sometime and you’ll instantly see how violent the jerk acceleration is when going into (or out of) the curves. I was thrown from my seat on the 511 when the driver floored it in the Exhibition Loop once!

They do have a few track lubricator spritzed throughout the system, although I think these are very new.

[tomh009]

Thanks, everyone. I didn't try the ride, but the screeching definitely is loud.

[KevinL]

I just educated myself about the difference between fixed-radius curves and transition spirals. Very interesting!

[Canard]

From the Functional Design Plans, you can see the four transition points identified as follows:

TS = Tangent to Spiral.  This is when the track moves from being straight, into the spiral (decreasing radius curve).
SC = Spiral to Curve.  This is the transition point between the variable-radius spiral, to the constant-radius curve section.
CS = Curve to Spiral.  Opposite of above.
ST = Spiral to Tangent.  Opposite of above.

(When the system was being built I kept seeing these marks on the pre-rolled curved sections when they were delivered, so I dug a little deeper. )

Without using a transition spiral, there is a hard jerk.  The analogy would be driving a car at some fixed speed and then suddenly jerking the wheel by turning it instantly say 90 degrees one way or another.  Once you're in the curve, holding the wheel... it's smooth because it's a fixed lateral acceleration that you are feeling.  But the rate of CHANGE was instantaneous - you jerking the wheel.  That's like going from straight to a fixed radius curve.

Spiral curves are the automotive equivalent of gently turning the wheel. The lateral acceleration (force) is applied gradually, so it feels smooth.

Steel roller coaster engineering took a good 2 decades to figure this out. All original Arrow Dynamics steel coasters had horrible, fixed-radius curves which result in slamming and banging and a very jerky ride. While the trains themselves would ride smoothly on the rails, any time the track went from straight to curved, you'd slam your head against the restraints. Probably the most violent example of this still around today is the Magnum XL-200 at Cedar Point - the return run back to the station is just brutal. I laugh every time I see it.

[jamincan]

Incidentally, jerk is the actual term used for the measured change in acceleration over time.

[tomh009]

Incidentally, jerk is the actual term used for the measured change in acceleration over time.

The second derivative of velocity!

[ijmorlan]

Steel roller coaster engineering took a good 2 decades to figure this out.  All original Arrow Dynamics steel coasters had horrible, fixed-radius curves which result in slamming and banging and a very jerky ride.  While the trains themselves would ride smoothly on the rails, any time the track went from straight to curved, you'd slam your head against the restraints.  Probably the most violent example of this still around today is the Magnum XL-200 at Cedar Point - the return run back to the station is just brutal.  I laugh every time I see it.

I thought that was part of the fun!

[Bob_McBob]

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