CN Flagging crossings in Pontiac

[MRC_Andrew]

While out on errands this morning, I noticed that there were flagmen positioned by at least two, possibly three, grade crossings in Pontiac. They were wearing hi-visibility vests and holding red flags and stops signs. They were at Woodward (two men), Rapid Street, and possibly South Blvd as well. The Woodward crossing also had a police car present. Are the signals out of service for some reason? Special move requiring extra attention? I don't know. Regrettably I couldn't stop and wait to see...

[coasterrider]

crossing protection for the Amtrak test train today. Testing the new coaches

[NS3322]

crossing protection for the Amtrak test train today. Testing the new coaches

Apparently they were not triggering all of the crossings...

[LansingRailFan]

crossing protection for the Amtrak test train today. Testing the new coaches

Apparently they were not triggering all of the crossings...

The coaches trigger the crossings or the engines?

[MRC_Andrew]

crossing protection for the Amtrak test train today. Testing the new coaches

Apparently they were not triggering all of the crossings...

Aw dang. Wish I'd been able to stick around. Didn't even realize an Amtrak test was imminent.

Thanks for the replies!

[SD80MAC]

crossing protection for the Amtrak test train today. Testing the new coaches

Apparently they were not triggering all of the crossings...

The coaches trigger the crossings or the engines?

Both.

[LansingRailFan]

Apparently they were not triggering all of the crossings...

The coaches trigger the crossings or the engines?

Both.

OK - so the engine would trigger the gates and then they would go up with the coaches not triggering the gates?

[SD80MAC]

Shunt must be properly maintained through the entirety of the crossing circuit in order for the gates to remain activated. If the coaches, for whatever reason, aren't properly shunting the circuit, that only leaves the 4 axles on each engine to maintain the shunt. The less axles you have, the greater the risk of losing shunt, particularly when the engines are spread out that far (front and rear) and at speed. This is one of the reasons why most railroads limit single light engines to 30 mph, any faster and the risk of losing shunt is too great. I've seen approach-lit intermediate signals momentarily go dark with single light engines in the block, moving. The more axles you have, the more contact points you have.

[PatAzo]

I'd wager an exercise in risk mitigation vs. an actual problem. Paste a car at a crossing and have a lawyer find out you were "testing" new equipment across a public roadway. What could be so different with these coaches that there would be an issue with crossing protection?

[NSSD70ACe]

I'd wager an exercise in risk mitigation vs. an actual problem. Paste a car at a crossing and have a lawyer find out you were "testing" new equipment across a public roadway. What could be so different with these coaches that there would be an issue with crossing protection?

I think it’s less crossing protection due to shunt failure and more ensuring that no one runs it and destroys a brand new coach.

And if it was indeed due to the legal issues involved with testing...then it would be a prime example of why I don’t like lawyers.

[PatAzo]

In the 1960's the NYC allowed light engines to run up to track speed not exceeding 60MPH.

[Doktor No]

Penn Central Northern Region ETT #3 April 27th 1969 page 83 states: MPH Single Light all classes except EP-20 and EP-22 30 MPH.
Engine class EP-20 and EP-22 50 MPH.
Ep-20 and EP-22 had a max speed of 98 MPH. I am thinking E-20 and EP-22 were EMD E7 and EMD E8 power. The ETT shows them by unit numbers.

[PatAzo]

I recall Conrail limiting light engines to 30MPH. As I understood it due to the locomotive nosing at higher speeds. I was looking to see what RDC cars might have been allowed to do and came across light engine speed. The ETT No. 19 April 1966 Detroit, Canada and Michigan Division says engines 1000 to 7608, 8056 to 8084, 9900 to 9913 "Light or with caboose limited to maximum track speed but not to exceed 60 [MPH]. They did limit 8047 to 8048 and 8092 to 9767 to 45MPH light engine. These look to be end cab switchers.

[ns8401]

Penn Central Northern Region ETT #3 April 27th 1969 page 83 states: MPH Single Light all classes except EP-20 and EP-22 30 MPH.
Engine class EP-20 and EP-22 50 MPH.
Ep-20 and EP-22 had a max speed of 98 MPH. I am thinking E-20 and EP-22 were EMD E7 and EMD E8 power. The ETT shows them by unit numbers.

Correct, E7’s and E8’s. How often did those go over the road without cars I wonder?

[kckorienek]

I'd wager an exercise in risk mitigation vs. an actual problem. Paste a car at a crossing and have a lawyer find out you were "testing" new equipment across a public roadway. What could be so different with these coaches that there would be an issue with crossing protection?

I think it’s less crossing protection due to shunt failure and more ensuring that no one runs it and destroys a brand new coach.

And if it was indeed due to the legal issues involved with testing...then it would be a prime example of why I don’t like lawyers.

No, it literally was for loss of shunt testing and to ensure no car/train accidents to delay the testing, there were a lot of people involved in this.

[PatAzo]

Why then 1966 would NYC allow a 60MPH light engine movement and three years later on essentially the same railroad run by the same people the limit dropped to 30MPH. I will theorize that behind the 60MPH ETT limit was a sheaf bulletins and slow orders reducing the limits where track conditions caused shunting issues. By 1969 traffic and maintenance were in the decline. Management had other issues to focus on and reason had set in. How many single light units really go far or need to run track speed?

I'd read some time ago a paper from the U.K. about light weight high speeds trains being more prone to shunt failures than conventional equipment. One of the chief causes was the equipment tracked better and the wheels skidded about less than older equipment. Not sliding wheels but a slight movement on the rail as the wheel sets repositioned on the rail due to variances in gage, tread profile and the rail surface. The skidding about tended to wipe away oxidation. The newer equipment essentially did not clean the rail I could not find it again but came across a PowerPoint with a nice explanation on "de-shunting".

https://international-railway-safety-co ... s-pres.pdf

Back to SD80MAC's experience with a light engine and pumping signals. Slower speed must give the wheel more time to push down through what is ever creating the higher impedance at the rail interface.

[DaveO]

Did they flag the other crossings on CN?

[justalurker66]

CN does like to have a higher axle count to ensure their systems detect trains.

One reason for the light engine speed limits is braking. Heavy engines that need a little help from the other cars in the train. On the South Shore in Indiana they have the following equipment restrictions:
Passenger Trains: NICTD, METRA or Amtrak Equipment .......... 79 MPH
Passenger Trains: equipment with freight locomotive .......... 65 MPH
Single locomotive unit, without Caboose .......... 30 MPH
Lite multiple locomotive, with or without caboose .......... 50 MPH
The passenger equipment is designed with sufficient braking for the consist (whether a two car EMU or a longer set with non-powered cars). Axle count alone does not explain why an eight axle passenger train can travel at 79 MPH and two or more lite engines (eight or more axles) are limited to 50 MPH on the same tracks. The difference in braking can explain that difference.

I agree with the thought that this flagging was being done out of an abundance of caution during the test.

[LansingRailFan]

Did they flag the other crossings on CN?

Yes they did. Also these Amtrak test cars tied up traffic in BC for a while as well.