Are axle counters fail safe?

Both track circuit and axle counters are in fact failsafe. This means that axle counters have a higher safety system performance than track circuits, thus making it ‘safer’ than track circuits.

What does a track circuit do?

A track circuit is a simple electrical device used to detect the presence or absence of a train on rail tracks, used to inform signallers and control relevant signals.

How do axle counters work?

An axle counter is a device on a railway that detects the passing of a train between two points on a track. A counting head (or detection point) is installed at each end of the section, and as each train axle passes the counting head at the start of the section, a counter increments.

Are track circuits fail safe?

The track circuit is a fail-safe device ensuring that any fault results in the signal light turning red, and in trains being prevented from entering the associated track section. However, this fail-safe property also has the potential to cause significant train delays if the system becomes unreliable.

What does number of axles mean?

The number of axles in a car depends on the type of vehicle, as Car From Japan states. In most cases, cars have two axles to rotate the wheels. Larger vehicles that carry more passengers and have more wheels may have more axles. It’s easy to identify the number of axles that your car or any other vehicle has.

How are trains detected?

A train is detected because it shorts the circuit. In railroading, this is called “shunting” the circuit. When a train enters a block, the metal wheels and axle conduct the circuit as a short cut which bypasses the relay. This de-energizes the relay, which causes signals to report the block as occupied.

How long is a track circuit?

The length is dependent on the frequency of the electrical signal, in which higher frequencies will have a greater loss of signal in transmission through the rail. Commercially available track circuits typically use lower frequencies or DC pulses and have a possible length of more than 5 miles.

What is track circuit failure?

What is a track circuit failure? A track circuit failure can delay trains because the signalling system is designed to fail to a safe state. Potential causes of failures include a broken rail, a blown fuse, faulty electrical parts, cable theft, or a loose connection, all of which form a break in the track circuit.

Which axle is the drive axle?

The drive axle is a split axle with a differential and universal joints between the two half axles. Each half axle connects to the wheel by use of a constant velocity (CV) joint which allows the wheel assembly to move freely vertically as well as to pivot when making turns.

Are train tracks energized?

Trains on some lines or networks use both power supply modes (see § Mixed systems below). All third rail systems throughout the world are energised with DC supplies. Some of the reasons for this are historical.

Why are axle counters more reliable than track circuits?

Added value: 1 Much higher reliability than in track circuits, resulting from the lack of connection with rails (resistant to lightning damage) 2 Axle counters are proved more reliable than track circuits (over 5 – 6 times, based on long time monitoring) 3 Resistant to poor ballast and track conditions

How does an axle counter work on a railway?

The push-trolley can be physically lifted off the track and kept aside. Even though the section is clear the system will show section occupied. To avoid this, a short two rail length closed track circuit is provided at each diction point and the transducer equipment of the axle counter is fitted within the track circuit.

How are axle counters different from closed loop circuits?

3. Axle counters, unlike closed loop track circuits, do not provide broken rail protection. Although there is a great deal of controversy in the industry as to the percentage of broken rails actually detected by track circuits before they are traversed by a train, axle counters will not detect any break whatsoever. 4.

How long can an axle counter system cover?

An axle counter system can cover a very long section up to 15 Kms. It does not get affected either by flooding of track or poor maintenance of tracks unlike the track circuit, which is highly susceptible to these conditions. It does not require insulating rail joints, thus, rails can be continuously welded.