Modern technology

Frank writes...

Okay, so this post is the result of my visit to IRM some two weeks ago, but I haven't been out since and what it makes up for in information it lacks in time-sensitivity. So I figured it would be okay posting this tardily. You're getting what I got when I stopped out on a Sunday afternoon: a primer in some of the most modern technology ever applied to an interurban car. In this case, it's a Houdaille rotary shock absorber off of CA&E 460, which was on the pit for its annual inspection.

Here's a photo of one of the shock absorbers in place. The car has four (as does sister car 451), one on each side of each truck, and they're designed to lessen the roll of the car by dampening the action between the truck frame and truck bolster. Houdaille made tons of these things, mainly for the automotive market, though those tended to be much smaller I was told.

Anyway, here's what one looks like disassembled on the bench in the shop. Richard, Greg, Joel, and Good Nick were working on this thing. It had been removed from the car and disassembled the previous evening in what was, by all accounts, a herculean team effort owing to incredible buildup of gunk and crud. Anyway, it's not a tremendously complex system. In the left foreground is the body, which bolts to the truck frame. There are four chambers inside the body; two of the dividers are cast into the body and the other two attached to the shaft, which rotates as the arm (attached to the truck bolster) moves. The arm to the right, fits right over the shaft after the top portions of the housing are installed. When assembled these chambers have hydraulic fluid in them, which originally would have been glycerin, and the rotary motion compressing and expanding the internal chambers provides the dampening action.

Here's the cover after quite a bit of cleaning. If I recall correctly, the top of the main chamber (visible in front of that McDonald's cup in the previous image) gets installed over the body and then this cover screws on over that, with the space between the top and cover used as a well for hydraulic fluid, filled using the port visible at the top of the cover. Hopefully Richard can comment with corrections of whatever I'm getting wrong here.

And here's what a cleaned and serviced Houdaille interurban rotary shock absorber looks like when it's been reassembled. All four of the ones on the 460 appeared to be complete and in generally good condition, but none seems to have any hydraulic fluid left in it and this one contained quite a bit of gunk and goop. The result is that there's no dampening force; they're pretty much just along for the ride. Once these are all rebuilt - and refilled, albeit not with glycerin - the car should ride more smoothly and roll less. Time to put this technology to work!