CC.Clive@R20.UTEXAS.EDU (Clive Dawson) (09/19/85)
By coincidence, I too have been watching track repairs over the last few days on a stretch of the Missouri-Pacific line which parallels the MoPac (what else?!) freeway through Austin. In this case, however, they are replacing old ties, not rails. The machines are magnificent. A small unit which pulls out the spikes leads the parade. This is followed by a giant crab-like monster which firmly plants four feet on the ballast, then uses hydraulic claws to grab both rails. More hydraulics are used to literally lift itself (plus the rails) up a few inches. Then another giant claw attached to the side comes into action, grabbing the tie and sliding it out sideways. At this point the details get sketchy--I can safely observe only so much driving at 55 MPH. I'm not sure whether the same machine installs the new tie, or whether this is left to a similar machine which comes along behind. (It may be that both units are each doing the full operation.) Finally, another machine comes along to reattach the rails, make sure of the spacing, etc. It's fun to measure their progress each day. On my return trip the new ties which littered the slopes beside the track are replaced by old, rotting pieces of lumber. Some of them are in amazingly bad shape for what I would think is an area of relatively benign climate (i.e. not that much rain, snow very rare). I too have a question for the experts, which I suspect is related to this very point: In general, how does the life of a rail compare to the life of a tie? Cheers, Clive -------