Dumping sand

Is sand ever dumped automatically when triggered by wheels losing adhesion or is it always under manual control?

all current locomotives trigger the sanders when wheel slip or emergency braking occurs.
Plus there is manual sanding available to Engineer.

Some railroads have a rule forbidding sanding in interlockings. Have there been any problems resulting from automatic sanding while passing through an interlocking?

The Railroad can prohibit all they want, there is no control over Automatic sanders other than turning of Circuit breaker.
But if you do that, and you need to dump air and need sand, it would become a liability issue.
plus under railroad rules the FRA would consider that, cutting out a safety device.

Thanks for the reply--I kind of thought there would be a conflict there. I guess if sand gets dumped in an interlocking they just have to live with it. In fact, even before automatic sanding, if an engineer was in a situation where sanding was necessary to keep something worse from happening, would that get the engineer off the hook as far as a rule violation was concerned? Or would that depend on what kind of superintendent they had?

in 30 years I never got challenged about use of sand, so I don't know

I understand that sanding over switches would defeat the lubrication on the plates. Oh well, the MOW has a little extra work. Our PTC equipped SD40s would sometimes sand for slips real or imagined. Sometimes it would only take opening or closing the throttle. This worried me more if I was running light. There have been accidents where a light locomotive stopped on sanded rail, and the sand insulated the signals. Boston and Maine had a wreck inside Hoosac Tunnel because a sander stuck open. This caused the following movement to hit a stopped light engine.

Unless the pile of sand is on the points AND big enough to interfere with the movement, thus causing an out-of-correspondence icon to light up on the Dispatchers board then it's just more dirt on the railroad as usual. Either way, good luck proving who left it there.

"Excessive use of sand is prohibited."

Sometimes you have to use every tool available to avoid stalling. I mentioned the worry about light engines sanding, then not shunting the signals. Thinking back, this is sort of a moot point. Many rule books require absolute blocks on short trains or drafts.

G'day,
Yes, here in NSW, the use of sand for traction is strictly regulated.
All locomotives must possess air blowers fitted behind the wheels to blow off any sand from the rail head after deposited for traction purposes.
After the Hawkesbury River incident where automatic signals returned to clear due to a stalled steam locomotive tour train, sand blowers were mandated.
The regulations also are strict in the amount of sand that can be deposited.
Automatic signals possibly returning to clear behind trains depositing sand for traction has been known for some time.
Quite different to the good ole days when you pounded the sand pedal constantly to maintain traction in wet weather.
Stevej.