Alex Jackson Dropper Location

davebradwell
Posts: 1173
Joined: Fri Jan 18, 2019 3:48 pm

Re: Alex Jackson Dropper Location

Postby davebradwell » Wed Apr 14, 2021 7:50 am

If the dropper can touch the ballast you're doing something wrong as the coupler is supposed to hit the axle first. This would not be acceptable the way we operate as it causes derailments. It would seem you may be cheating - dropper is probably too low in the first place. With the Lanarkshire droppers, the movement could be limited with a loop of wire.

Chris's article raises concerns about pivoted a/js. If they're too short, there isn't enough sideways spring for the couplings to swap sides when uncoupling. Also if using the 3 link as a dropper, if fitted to adjacent vehicles, there is a danger of pulling both down and they will remain coupled.

DaveB

User avatar
Will L
Posts: 2516
Joined: Sun Jul 20, 2008 3:54 pm

Re: Alex Jackson Dropper Location

Postby Will L » Wed Apr 14, 2021 8:18 am

I don't use AJs but isn't the point of having the dropper just behind the axle is so that the axle forms a stop that prevents the dropper touching the track?

Edit, Sorry Dave I missed your post.

dmsmith
Posts: 18
Joined: Mon Jul 28, 2008 6:34 pm

Re: Alex Jackson Dropper Location

Postby dmsmith » Wed Apr 14, 2021 11:53 am

@DaveB ... You are right! My assumption in experimenting had been that there wouldn’t be sufficient pull, so I set the conventional droppers as low as I could, and probably lower than specified. Having said that, the pull from the Dingham magnets at 12 V DC is sufficient to bend the wire of the coupling when the dropper is directly above the magnet, even when the wire is touching the axle.

The challenge is slightly different with the Lanarkshire droppers. The vertical movement is greater than for conventional droppers mounted behind the axle, which are therefore closer to the fixed point. That means that the bottom of the Lanarkshire coupling needs to be higher above the track. That distance is defined by the dimensions of the couplings, but the movement could indeed by constrained by a loop.

Best wishes
David

davebradwell
Posts: 1173
Joined: Fri Jan 18, 2019 3:48 pm

Re: Alex Jackson Dropper Location

Postby davebradwell » Wed Apr 14, 2021 2:12 pm

While you're experimenting, David, it would be worth applying power to the coil and seeing if it can be left unnattended. Even a continuously rated solenoid will get too hot to touch but you don't want any smoke.

I thought you were just agreeing with me Will and there's not many folk do that! One or two recently, perhaps.

DaveB.


Return to “Couplings”

Who is online

Users browsing this forum: ClaudeBot and 0 guests