how to keep a stopped train from rolling

[NorthWest]

Paul, I think so! Is it in the article about QNS&L from a couple years ago?

[Euclid]

The TSB report of the MM&A runaway mentions chocks as a defense against runaways, although I think Overmod is correct in his assessment of the practical problems chocks pose.  Actually, I am surprised that the TSB report mentions them, although they do so only as a generic comment about various means to secure trains, and not as something that would have been practical for securing long trains on mainline grades. 

I think it is more important to make a distinction between degrees of risk.  Many trains are secured where a runaway would have a good possibility of doing little damage.  And many trains are carrying loads that will cause little collateral damage if they should derail.  But the complete opposite of these innocuous conditions was the MM&A oil train parked atop the grade leading into Lac Megantic. 

Here the stakes were way too high to rely on a system affected by the variables of the number of handbrakes generally assessed to be sufficient by a variety of reinforcing means and human judgment.  For such a risky proposition, a modern, 21^st Century securement method is called for. 

[Paul_D_North_Jr]

"WAG": Might have been on the Quebec North Shore & Labrador ?

[NorthWest]

Note that there are rail chocks, but they are used for singular cars at industries.

I saw a picture of the airbrake hose that clamps to the rail a while ago, but can't find it. Can anyone help? It looked rather improvised.

[Overmod]

Fundamental issue with chocks is that the mass of the train is so enormous that a chock made of portable material will be smashed or rolled over, or will simply be pusned down the railhead ahead of a locked wheel (there being very few ways to 'tie the chock down'  that will survive that kind of loading without becoming a random-derailment hazard to a degree, or causing potentially serious damage to the railhead or other parts of the track structure).  And calculate the cost for me of providing chocks for each car, plus welding on the brackets to hold them, and securing them to keep random folks from removing them for 'souvenirs', doorstops, window-smashing projectiles, nifty ways to derail speeding trains without warning, etc. while retaining the ability for dog-tired railroaders to get them off to use them.

Meanwhile your crew must physically obtain the chocks from wherever they are stored, then walk with each one to the location it's to be deployed, and ensure it's secured -- and then another crew has to walk to get each one and re-stow it, being certain to get every one.  If that 'crew' is one tired person, in the dark and perhaps in storm, that's not really a rational option -- especially compared to proper use of existing handbrakes and a proper securement test.

There is also the question of what happens if a train with chocked cars builds up momentum and the chock then 'catches' on something.  What is likely to ensue is a derailment -- almost certainly a more dangerous one than occurs when intentionally derailing within a few feet after the consist starts to move.

[gardendance]

I asked Steve Sweeney what happened to thread on train securement, which has been deleted. He replied that it was the fairest thing to do considering their other obligations, but didn't explain what the reason was. He didn't tell me that I had done anything wrong, although I don't remember if I had posted anything in that thread. If any of you did get explanations that said there was something wrong with what you posted, I'd appreciate it if you wouldn't do it again, since that will probably cause the moderators to decide to punish those of us who want legitimately to discuss this.

There were several posts, some of which gave me headaches, which seemed to try to explain a lot of the advantages and disadvantages of various ways to keep a stopped train from rolling. I thank the fellows who took the time to explain it, and hope you'll try to recreate your well thought out explanations.

I don't remember anybody mentioning chocks. The 500 ton gorilla in the room of course is the Lac Megantic disaster. In one of those threads I think I remember asking what would a couple of chocks have done, somebody replied that the chocks would have been turned to splinters. Could somebody explain why, or what would a sufficient number of chocks be to secure a given number of railroad cars, and why other methods might be better than using chocks?

In my layman's opinion I think it'd be a lot easier to tell if somebody's set chocks, and one could tether them to the carbody, so one would not need to carry them, but rather secure them to the carbody when they're not using them. That sounds to me like an easier thing to do than set and release handbrakes.