Axle Counters vs Track Circuits Quiz & Flashcards

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Questions and Answers

Which statement accurately describes the purpose of an evaluator in an axle counter system?

It serves as a manual override for track circuits.

It operates the signals based on real-time weather data.

It monitors the counts from axle detectors to provide indications. (correct)

It physically inspects the track for obstructions.

In which scenario might a Digital Axle Counter (DAC) be preferred over DC track circuits?

On girder bridges. (correct)

In densely populated urban areas.

Where conventional track circuits have been installed.

In standard flat track installations.

What type of wheels are excluded from being counted by axle counters?

Standard 4 spoke wheels of push trolleys. (correct)

Standard 6 spoke wheels.

Heavy-duty train wheels.

Specialty racing wheels.

Which application is NOT mentioned as a typical usage of axle counters?

High-speed rail operations. Signup and view all the answers

What is a critical feature to consider during the installation of axle counters in areas with trolleys?

Implementing a trolley suppression arrangement. Signup and view all the answers

Which of the following is a recommended application for axle counters?

Areas with poor drainage or flood-prone zones. Signup and view all the answers

Which aspect of axle counter installation requires adherence to specific guidelines?

Installation guidelines and pre-commissioning checklist. Signup and view all the answers

Which condition should be addressed to ensure balloon detection of certain motor trolleys?

Their operation requires exemptions outlined in working rules. Signup and view all the answers

What is the purpose of deflectors provided on both sides of the axle detectors?

To protect against damage from moving train parts Signup and view all the answers

What is the minimum required distance between two adjacent axle detectors of different axle counters?

2 meters Signup and view all the answers

How should the transmitter and receiver coil cables be laid according to the manufacturer?

In different pipes as prescribed Signup and view all the answers

What feature will future digital axle counters include?

Inbuilt trolley suppression provision Signup and view all the answers

What is the maximum allowed ripple in the input power supply for track side electronic equipment?

50 mV peak to peak/10 mV rms Signup and view all the answers

Which type of power supply is preferred for operating track side electronic equipment?

Central DC–DC converter of approved type Signup and view all the answers

What is the required sleeper spacing between the track device sensors?

400 mm Signup and view all the answers

Where should the evaluator be installed for optimal security?

In a relay room or inaccessible location Signup and view all the answers

What must be done before resetting the axle counter after a fault condition?

Verify clearance of the block section with the Assistant Station Master. Signup and view all the answers

How is the reset box for the axle counter operated?

With a key that is kept locked in a separate box. Signup and view all the answers

What should happen during the axle counter reset operation?

Both the dispatching and receiving stations cooperate in the reset operation. Signup and view all the answers

What must be recorded in the Train Signal Register after a reset operation?

The movement of the train before and after the reset. Signup and view all the answers

What is the purpose of the non-resettable counter in the reset box operation?

To ensure no operation is accidentally erased. Signup and view all the answers

What role does the Signal and Traffic Inspecting official play during inspections?

They ensure private number exchanges are followed properly. Signup and view all the answers

What should be included in the Station Working Rules regarding the axle counter resetting?

A procedure for piloting the first train after a reset. Signup and view all the answers

What is the consequence of a fault condition in the axle counter?

The concerned signal cannot be taken off. Signup and view all the answers

What is the maximum ripple allowed in the input power supply for the evaluator?

50 mV peak to peak Signup and view all the answers

What should be the minimum distance between wires from the battery and DC-DC converter and other bunches of wires?

150 mm Signup and view all the answers

Why should positive and negative wires be twisted together?

To avoid interference pickup Signup and view all the answers

What type of cable is recommended for communication with axle counters?

Optical Fibre Cable (OFC) Signup and view all the answers

What voltage drop should not be exceeded for lead connections to and from the battery and DC-DC converter?

0.2 V Signup and view all the answers

What power supply feature enhances the availability of evaluators?

Dedicated DC-DC converter for each evaluator Signup and view all the answers

Redundant train detection devices must be powered through what?

An independent power source Signup and view all the answers

Where should the equipment be installed to avoid flooding?

At a high level, above the flooding area Signup and view all the answers

What is the first step to take for resetting an axle counter after it has failed?

Verify that the line for the train is physically clear of any obstruction. Signup and view all the answers

Who is responsible for operating the line verification box during the resetting procedure?

The on duty ASM and another Operating Staff member. Signup and view all the answers

Where should the key for the reset box be stored?

In a locked box secured in the Station Master's office. Signup and view all the answers

What must be recorded by the ASM after operating the reset button?

Each operation of the reset button in the Train Signal Register. Signup and view all the answers

What should inspecting officials check during their inspection regarding the axle counter resetting procedure?

If laid down procedures for resetting are being followed. Signup and view all the answers

What specific procedure must be confirmed before resetting the axle counter?

The monitored portion must be free of any vehicle. Signup and view all the answers

What signal must be received by the first train after the reset operation?

A calling-on signal or be piloted per existing rules. Signup and view all the answers

What must be installed close to the line to facilitate physical verification of a failed track section?

A line verification box (LV box). Signup and view all the answers

What should be done if an Axle Counter fails after resetting?

Treat it as failed and advise Signalling maintenance staff immediately. Signup and view all the answers

Which staff member is responsible for ensuring the condition of the anchoring of tracks near axle counters?

Permanent Way staff Signup and view all the answers

What is the maximum distance deviation allowed between the two rails in double rail mounted track devices?

There should be no deviation beyond permissible tolerance. Signup and view all the answers

What maintenance activity should NOT be performed on the 4 sleepers adjacent to track devices for axle counters?

Use of a Tie Tamper Signup and view all the answers

What must be ensured during maintenance activities that involve disconnection of track devices?

Work should only be done in a non-operational system. Signup and view all the answers

What is the purpose of resetting the axle counter?

To ensure accurate count of axle movement. Signup and view all the answers

Who is responsible for making sure that replacement components of Axle Counters are handled carefully?

The Signalling maintenance team Signup and view all the answers

What should the on-duty ASM at the point zone/loop line ensure for the axle counter operation?

The axle counter shows 'clear' after an operation in the column. Signup and view all the answers

Study Notes

Axle Counters - General

Axle counters are track devices (axle detectors) mounted on rails, linked to trackside equipment (near the track) and an evaluator.
The evaluator monitors track device(s) counting, providing clear/occupied signals. Evaluator/trackside equipment might be in a relay room or on-site.
Digital Axle Counters (DACs) can replace track circuits for proving portion track clearance.
Axle counters are used for intermediate block stop signalling, automatic block signalling, station sections with poor drainage/flood proneness, Block Section Proving of Clearance (BPAC), and tracks needing rust prevention. They're also suited for tunnels/bridges as per site requirements.
Axle counters don't count 4-spoke push trolley wheels. Specific provisions in station working rules, timetable, and subsidiary rules might be required for certain trolley types.
Trolley suppression systems are needed in sections with trolley operations on existing axle counters without such a feature.

Installation of Axle Counters

Installations follow OEM guidelines and reviewed pre-commissioning checklists.

Installation Procedure Details

Trolley suppression: Existing axle counters without built-in suppression need extra measures for insulated trolleys. Trolley suppression safeguards the system from trolley actions. Non-metallic wheeled trolleys often don't need them.
Detector spacing: Axle detectors should be at least 2 meters apart to reduce mutual interference (as per OEM manuals).
Protection and Placement: Deflectors on axle detectors protect them from moving trains (single line = one side, double line = both sides).
Electrical Equipment Location: Trackside equipment needs to be close to the axle detectors for minimized cable lengths which adhere to manufacturer recommendations. Location should be above expected flood levels.
Cable Management: Incoming cables should pass through a distribution board for testing. Axle detector coil cables should be housed in different pipes, per OEM requirements.
Sleeper Spacing: Maintain a 400mm minimum spacing between sleepers and track devices. Fitting should not vibrate during train movement, and packing should be done if required.
Electrical Supply: Axle counter equipment's Central power supply is from DC-DC converters (approved type), with backup batteries. Remote units might need separate power supplies. 50mV peak-to-peak (or 10mV rms) maximum ripple is the input limit for the supply.
Location & Protection: The evaluator needs to be in a relay room or non-public area. It has to be above flood levels and protected from rain. Avoid interference sources like heavy machinery, motors, generators, or welding equipment.

Axle Counters Resetting

Block Section/Intermediate Block Signalling/Automatic Signalling: These types of sections require preparatory reset arrangements. The on-duty Assistant Station Master (ASM) or Station Master (SM) confirms clear paths and performs a cooperative reset action between dispatching and receiving stations. On-duty personnel verify clearance, record details in the Train Signal Register (TSR), and follow station working rules procedure.
Station Section:
- The cooperative system is used for point zones, loop lines, and sidings. The SM verifies the section's clear path before resetting.
- Main lines/Run-through lines: The reset box (locked in the SM's office) is used. Each button press is recorded in the Train Signal Register. The reset button's procedure is monitored during inspections.

Maintenance

Maintenance adheres to RDSO guidelines and equipment manufacturer recommendations.
Double-rail track devices prevent differential creep that alters inter-rail distances. Four track lengths are to be well anchored on either side for this purpose.
Track anchoring should be carefully monitored by the Permanent Way staff to ensure no creep.
Tie tampers shouldn't be used for four sleepers on either side of the track devices. They should be maintained manually.
Replace axle counter components carefully, considering technical manuals.
Avoid interruptions during work on axle counter sections by disconnecting parts first, ensuring equipment de-energization, and following safety protocols for related sections. If procedures don't involve changing system functionality, the procedures may occur without disconnection.

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Description

This quiz covers the essential concepts and functionalities of axle counters, including their applications in railway signaling and track monitoring. Learn about digital axle counters, their advantages, and specifics like trolley suppression systems. Explore how these devices help ensure track safety and reliability.

Axle Counters - General Overview

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