Railroad switch

A railroad switch, also known as points or turnout, is a mechanical installation enabling trains to change tracks, crucial for rail network efficiency.

About this subject

A railroad switch, also known as points or turnout, is a critical component of railway infrastructure. It consists of movable rails that guide train wheels from one track to another, allowing trains to change routes without stopping. Switches can be operated manually with levers or automatically through electric or hydraulic systems controlled by signaling centers.

There are various types of switches, including simple turnouts, movable frog switches, and double junctions. Each is designed for specific speeds and loads: high-speed switches feature smoother geometry and more wear-resistant parts. In countries like the United States, standards from the American Railway Engineering and Maintenance-of-Way Association (AREMA) govern design and maintenance.

Historically, the first switches appeared in early 19th century England, using wooden movable rails. The modern switch was patented by Charles Fox in 1830. Since then, advancements have allowed switches to handle heavier trains at higher speeds. Safety is paramount: a misplaced or malfunctioning switch can lead to derailments.

Maintenance involves regular inspection, lubrication, gauge measurement, and component replacement. On busy corridors, such as the Trans-Siberian Railway in Russia, switches are replaced every few years due to intense wear. The failure of a single bolt can disrupt the entire system, highlighting the importance of rigorous upkeep.

Frequently Asked Questions

How does a railroad switch work?

A railroad switch uses movable rails called 'switch blades' or 'points' that slide laterally to guide train wheels onto one of two diverging tracks. The mechanism is operated by levers or electric motors, with automatic locking to ensure correct alignment.

What are the main types of switches?

The main types are simple turnouts, movable frog switches, and double junctions. Simple turnouts are common in yards, while movable frog switches are used on high-speed lines to eliminate gaps in the crossing.

Why are switches important for railway safety?

Switches are critical points where failure can cause derailments. Proper maintenance and signaling systems prevent accidents. A malfunctioning switch can lead to unintended route changes or blockages, disrupting traffic and risking collisions.