Hump Shunting, Gravity Locos, One Way Locos...

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Sometimes wagons can be routed to the right track via setted railway points.
As a matter of fact, technical specifications content articles for vertical curves on maneuvering areas for safety (to prevent the wagon runaway). According to those articles, warehouse and workshop lines must have ramp to the main line on the output direction.                                                     
 Sometimes ramps can contain decelerators as well. Sometimes ramps can contain decelerators as well. There are several different designed and patented decelerator.
Hakan N. Öztürk

References :
https://www.youtube.com/watch?v=_a2Y-ho5eiY / Ivo Radoev
https://www.youtube.com/watch?v=V0l4v9z5-oI / JCS Trains
https://www.youtube.com/watch?v=083uRhq8PGQ / Mixed Gauge Videos
Music :
Tom Petty - Free Fallin'