lenaitch
Senior Member
It was explained either upthread or in a different thread that the problem only applies to 'predictive' crossing signal technology, which is apparently not installed on the CN Bala or Newmarket subdivisions.
|
|
|
- Thread starter ehlow
- Start date
Trackside_Treasure
Active Member
Apparently CN listed some New Market [sic] Sub crossings in the Crossing Supplement in case of detours.
smallspy
Senior Member
As I wrote above and Eric correctly points out, there are a handful on the Newmarket Sub.
But the time loss of slowing from 60mph or 50mph down to 45 and then back up is far less than the time loss of slowing down from 95mph and then regaining that speed. Thus the amount of time lost by the Northlander sets will likely be in the single-digit minutes.
Dan
crs1026
Superstar
Funny how this comment triggered a rabbit hole excursion.... I had never really thought through the math.
If a train is travelling at 95 mph....a correctly functioning predictor circuit providing 22 seconds of crossing protection will activate the lights and bells when the train is 3065 feet from the crossing.
At 60 mph, the crossing protection will activate when the train is 1936 feet from the crossing.
At 45 mph, the protection will activate when the train is 1452 feet from the crossing.
At 95 mph, assuming perfect sightlines and visibility, the train may be say 2500 feet away before the crew is certain that the protection has failed and the train needs to stop and protect. A venture train will likely not stop from 95 mph, even with an emergency brake application, in that distance (I won't guess at the actual braking statistic). Hence the requirement to be down to 45 mph before the protection activates. At 95 moh, given curvature and real life conditions, the crew will likely not be able to confirm protection is working in time to stop safely if it isn't.
The theoretical penalty zone from 60 to 45 is shorter by about 1000 feet versus 95 and the deceleration zone to get there is likely much shorter. I doubt that a venture set could go from 60 to 45 in 484 feet, so the 60 mph venture will still need to begin braking before it hits the 60 mph trigger point, and that moves the effective trigger point towards the 45 mph trigger point. So there is still some time and mental effort consumed before the crew sees everything is ok.
That's the limit of my math skill, but there it is.
- Paul
smallspy
Senior Member
Just to muddy the waters even more.....
With a predictor level crossing circuit, the equipment will detect and calculate the speed of the train something like 3500 feet out from the crossing.
So in the case of the Siemens sets, it detects it at its higher speed, and if working correctly activates as if the train was traveling at that speed all the way to the crossing.
But because the train slows down to about 45mph, the gates and lights are activated for considerably longer than would otherwise be the case.
Dan
crs1026
Superstar
And just to muddy the waters further again…. I have never heard of a crossing circuit that activates and then gives up without performing its full cycle. So once something, anything, triggers the gates and they start to come down, they provide the required 22 seconds of protection before they open up…. Even if the trigger stimulus was false and only momentary.
Which ought to imply that once a crew sees the gates operating, they ought to be allowed to throttle up immediately and return to full speed. The requirement to come all the way to 45 and hold it to the crossing notwithstanding a correct activation of the protection seems doubly restrictive and unnecessary….. but I’m not a signals engineeer.
- Paul
Which ought to imply that once a crew sees the gates operating, they ought to be allowed to throttle up immediately and return to full speed. The requirement to come all the way to 45 and hold it to the crossing notwithstanding a correct activation of the protection seems doubly restrictive and unnecessary….. but I’m not a signals engineeer.
- Paul
Trackside_Treasure
Active Member
CN only put a “time” restriction on VIA, ensuring the gates are horizontal from 20-25 seconds. VIA took it a step further and said “do 45 at the whistle post”. But now VIA doesn’t want to loosen that. There are often times when the crossing can be seen working from a mile away, so to follow CN’s instructions a train would barely have to drop its speed. It’s VIA that put the crippling blow of reducing to 45 regardless of knowing the crossing is working as intended. Very counterintuitive. Something about a couple of VIA guys playing at the simulator!
crs1026
Superstar
Possibly (again, beyond my math) there is a scenario where the gates activate, but having already slowed to 45 the train is now more than 22 seconds away from the crossing.. so if the detection fails, the gates will cycle off befor the train hits the crossing.
Just a theory.
- Paul
dowlingm
Senior Member
Now that the Hamilton West Harbour eastbound exit track is operational, has VIA provided any indication that they might now stop there on the joint service with Amtrak? Or does that introduce too many operational complications?
Urban Sky
Senior Member
Given that the existing stop in Aldershot is so close, and the train only matters for cross-border travel, I struggle to see the utility of adding a stop in Hamilton…
Last edited:
nfitz
Superstar
You could use that argument to stop VIA trains in St. Lambert rather than Central (which are even closer together than Hamilton and Aldershot. Which would save considerable time on the Ottawa to Quebec City train.
Hamilton is a no-brainer based on the urban fabric. Whether they keep Aldershot or not, I don't know.
The issue on that 14-hour train trip to New York City isn't whether they stop for a few minutes in Hamilton!
Bordercollie
Senior Member
London bound trains would stop at Aldershot. Niagara bound trains would stop at both. Is that so hard? What's an additional 5 minutes?
nfitz
Superstar
Because it would take 14-hours to get to New York City, rather than the current 13:55.
Obviously trains are going to stop in Hamilton.
micheal_can
Senior Member
The issue is you will be running the wrong way for part of that route which complicates matters. There is no way to go west from Hamilton without going back down the way they came.
Urban Sky
Senior Member
This is so obviously silly that it‘s not clear to me why it would merit a serious response...
Adding a stop is a decision made by comparing the incremental costs with the incremental benefits to determine whether the latter can possibly offset the former.Because it would take 14-hours to get to New York City, rather than the current 13:55.
Obviously trains are going to stop in Hamilton.
The cost of stopping at Hamilton is that only the tracks laid by Metrolinx have a platform at West Harbour GO station and that you therefore limit the number of possible routings in the Hanilton area. The only benefit of stopping at Hamilton is to passengers travelling beyond the border, as for all possible destinations on the Canadian side, GO provides a more frequent, less expensive and more reliable service.
In other words: would you risk seeing Train 97 being regularly delayed by 5-15 minutes at Hamilton Junction waiting for a path to clear into West Harbour GO station just to pick up 2-3 passengers which would have otherwise (been) driven to Aldershot instead?
The calculation becomes very different once Hamilton can actually be served by a usable intercity rail service (or platforms are added to the outer CN track), but until then, adding this stop would likely make the service even less and not more attractive…