Posts tagged “grinding”

Industrial-grade Smoothing

Orinda, BART, Late Night Originally uploaded by DCVoyager.

This SF Chron article describes a weird piece of behind-the-scenes infrastructure – the nightly grinding of the rails on the BART system (emphasis here is on reducing the squealing noise but presumably there are other safety and function reasons)

“But we don’t do that. We have to grind the rails.”

And that can be done only in the middle of the night, roughly between the hours of 1 and 4 a.m., when the passenger operation is shut down for the day to allow for track inspections and maintenance. It’s one of the reasons BART doesn’t operate on a 24-hour schedule.

Each night, crews smooth about 1 mile of track, just a sliver of the 104-mile system. It sometimes can take a dozen or more passes along one small section to get the track “just right,” said Dave Alves, who has worked the job for eight years.

On a recent night, Alves was the track man. Like a tailor judging a fine piece of fabric, he relies a lot on touch to determine how the track should be reshaped. He creates a grinding pattern based on the track’s marred surface and keys it into a computer that controls 20 grinding stones attached to the belly of a specially made railcar.

“Sometimes we may do 18 or 20 patterns on one piece of rail.”

They’ve got one car to do this task, and it’s a decade old. A new car takes more than a year to build (at a cost of $3M) since the BART rail size/width is non-standard.

Thought this was an interesting process story; the slow, non-automatic, manual nature of the task, and the analogous challenges in creating the tool for this task.


About Steve