🚦 Module 13B - Testing Microlok Units

Testing Microlok Units


Testing Microlok units is a critical part of railroad signal safety. The purpose of testing is to make sure the Microlok hardware, software, wiring, field equipment, and vital logic operate correctly.

Because Microlok controls safety-critical signal functions, testing must be performed carefully before the system is placed into service and throughout the life of the equipment.

1. Factory Testing

Factory testing is performed before the equipment is installed in the field. This testing checks the processing unit, input modules, output modules, communication ports, power supplies, and system configuration.

Factory testing helps verify that the Microlok equipment is operating correctly before it is shipped or installed.

2. Logic Testing

Logic testing verifies that the programmed interlocking logic works as designed. This includes checking routes, signals, switches, track circuits, locking, timers, and approach conditions.

The logic must prevent unsafe conditions such as conflicting routes, signal clearing into occupied track, or switch movement under a train.

3. Simulation Testing

Simulation testing allows engineers to test Microlok logic before the system controls real field equipment.

Simulated inputs can be used to represent track occupancy, switch positions, signal requests, route requests, and failure conditions.

4. Field Testing

Field testing is performed after the Microlok equipment is installed. This testing verifies the actual wiring, inputs, outputs, field devices, and interlocking logic.

Field testing confirms that signals, switches, track circuits, relays, lamps, cables, and control circuits operate according to the signal plans.

5. Functional Testing

Functional testing confirms that the system performs the required railroad signal functions. This includes route locking, signal clearing, signal dropping, switch correspondence, approach locking, time locking, and release functions.

6. Diagnostic Testing

Microlok diagnostic tools help technicians view system status, input conditions, output states, alarms, event logs, communication status, and fault information.

Diagnostics are useful during commissioning, troubleshooting, and routine maintenance.

7. Maintenance Testing

Testing does not stop after the Microlok unit is placed into service. Ongoing maintenance testing helps confirm continued safety, reliability, and proper operation.

Maintenance testing may include checking logs, verifying inputs and outputs, testing field devices, confirming communication health, and correcting any faults found during inspection.


Module Quiz

1. What is the main purpose of testing Microlok units?





2. What is typically verified during field testing?





3. Why is ongoing maintenance testing important?