Track inspectors put a slow order on track that cannot safely carry full speed: soft ballast, a fresh rail plug, a bridge repair, a hot afternoon on welded rail. The restriction appears in the crew's track bulletins with milepost limits and a speed, often 10 or 25 mph, and many railroads mark it on the ground with signs or flags. A line full of slow orders runs slow, so the slow order count is a common yardstick for a track department.
Watch it at MP 212, there's a 10 mph slow order for the new plug, and they haven't pulled the flags yet.
Running 10 mph or more over a speed restriction can cost an engineer the certificate, so engineers keep their own list of every slow order on the trip.
Also heard as
- speed restriction
- TSR
Related terms
MP
Milepost: the numbered marker that fixes every location on a railroad by distance along the line.
Plug
A short piece of rail cut into the track to replace a section with a defect or a break.
Sun kink
A sideways buckle in welded rail caused by heat, which can throw the track out of line under a train.
Restricted speed
A speed slow enough to stop within half the distance you can see, used whenever the track ahead may be occupied.
MOW
Maintenance of way: the department and crews that build and maintain track, bridges and roadbed.