axle counter

Some manufacturers provide axle counter equipment which is fail safe in design.

Axle counters were first introduced in the 1960s in Germany.

Axle counters may 'forget' how many axles are in a section for various reasons such as a power failure.

Axle counters are also useful on long sections where several intermediate track circuits may be saved.

Although axle counters can provide similar functionality to track circuits, they also exhibit a few other characteristics.

They can sometimes be mistakenly detected by axle counters as another axle.

Unlike track circuits, axle counters do not require insulated rail joints to be installed.

Where there are interlocked turnouts, an axle counter unit needs to be provided for each leg of that turnout.

Axle counters offer no such facility.

Axle counters only provide intermittent positive indication of a rail vehicle as it passes a fixed location.

Axle counters cannot detect any broken rails.

Axle counters have problems maintaining correct counts when train wheels stop directly on the counter mechanism; this is known as 'wheel rock'.

Electronic count heads are used in axle counter circuits that can replace track circuits completely.

An accident occurred in the Severn Tunnel and is thought to be due to improper restoration of an axle counter.

There are four methods of securing the reset and restoration of axle counters into service:

Among the upgrades are axle counters, mounting of an overhead conductor rail, new switches and new tracks.

The control center computer receives information about occupied blocks from track circuits or axle counters and locked routes from interlockings.

An axle counter is a device on a railway that detects the passing of a train in lieu of the more common track circuit.

Axle counters are particularly useful on electrified railways as they eliminate traction bonding and impedance bonds.

Another alternative is the axle counter, which can reduce the number of track circuits and thus the number of insulated rail joints required.

I understand that the signalling and axle counter system, which is used to detect the location of trains in the tunnel, was not working normally at the time.

In older installations the evaluators may use eight-bit logic, causing numerical overflow when a train with 256 axles passes the axle counter.

In August 2005, Michael Tien announced that 90% of breakdowns of the signalling system are due to failure of axle counters.

Axle counters require no bonding and less cabling in comparison to track circuits, and are therefore generally less expensive to install and maintain.

Axle counters are used in places such as wet tunnels (such as the Severn Tunnel), where ordinary track circuits are unreliable.