Canadian TSB Accident Report on Aldershot Derailment

[jis]

Canadian TSB has published their report on the derailment at Aldershot a while back.

http://www.bst-tsb.gc.ca/eng/rapports-reports/rail/2012/R12T0038/R12T0038.asp

 

[OBS]

Great report, thanks for posting.

 

[Ryan]

Concur.

Holy crow, this thing is long! Still plowing through it, lots of good info.

 

[jis]

OBS, you are most welcome!

Ryan, Yeah, I got to learn all those weird Canadian signal aspects and corresponding rules.

It had occurred to me back then and is confirmed after reading the report that if the US DIB rule were in effect in Canada this accident would have most likely not occurred. It looks like the crew plain forgot they had passed a double yellow (Rule 409) before stopping at Aldershot, and then possibly misread the signal protecting the crossover as FY-FG-R (Rule 406 - something consistent with having passed the previous signal in the clear) instead of R-FY-FG (Rule 432 - unexpected if you recollect that the previous signal was clear, but expected if you remembered it to have been double yellow). Of course the DIB rule in the US was written in the blood of an Amtrak-MARC encounter outside Washington DC.

 

[Bob Dylan]

Thanks jis, I have ridden thru Aldershot many times on Corridor Trains, Go Trains and the Maple Leaf and still wonder why they don't stop in Downtown Hamilton which is a Major Canadian City! :unsure: If you think the English Version is Long, think about the French one!

 

[The Davy Crockett]

Of course the DIB rule in the US was written in the blood of an Amtrak-MARC encounter outside Washington DC.

Funny. As I was reading your post, this incident came to mind as an example of a violation of said rule until I got to this sentence.

 

[Ryan]

Indeed - I said to myself "sounds like the MARC/CL incident in Kensington!" as I was reading the report.

It's a shame that for all the Amtrak related info that they're obviously aware of that the delayed in block rule hasn't made it up there.

 

[George Harris]

Could have simply been so familiar with the area that they were mentally running on autopilot without realizing that things were happening differently this time.

A speed limit of 15 mph over a No.12 turnout with 22 foot straight points is very conservative. With long curved points as described in the report, that was extremely conservative. 20 mph would be more usual on this size turnout with straight points. 25 mph would be beyond the norm with straight points, but would be OK with the long curved switch points. A speed of 30 mph through this turnout with the long curved point would be a step to far in my mind, not because of safety it woudl be well within the limit of safety, but because of the wear rate on the rail and the ride quality jerk rate. To give some scale to this, 15 mph speeds through No. 8 turnouts are the usual unless the overall track condition is poor. The old "rule of thumb" was that the speed through a turnout could be up to twice the frog number, in other words, 24 mph through a No. 12.