This model train set blog will list various railroad terms over the next few postings. Here are some more:

Demurrage
Tariff charges assessed for detaining freight cars beyond their specified time limit.

Derail
This track safety device is designed to guide a car off the rails at a selected spot. Its purpose is to protect against collisions or other accidents.

Dispatcher
The person in charge of all movements (and issuing Form D’s) within a designated region. Abbreviated as Dspr.

Disturbed Track
A section of track with a temporary speed restriction due to track maintenance or a defect.

Draft Force
Pulling force (tension) on couplers and draft gear during a slack-stretched condition.

Draft Gear
This is a cushioning device that transmits draft or buff forces between the coupler and the locomotive or car.