If the cab signal and fixed signal do not conform, the ___________________________________ will govern movement through the block.

If the cab signal and fixed signal do not conform, the ___________________________________ will govern movement through the block.

• A. More restrictive signal indication
• B. Cab signal priority
• C. Least restrictive indication
• D. Dispatcher instruction only

Answer: (A)

When two signaling sources don’t agree, you operate under the more restrictive indication. This keeps you from exceeding a restriction shown by either system and prevents entering a block under a condition that’s more limiting than it appears. In practice, cab signals provide in-cab speed and authority, while fixed signals give the track-side authority. If they don’t conform, you must follow the stricter instruction. For example, if the fixed signal shows a restrictive aspect or stop, you must obey it even if the cab indicates you may proceed. Conversely, if the cab shows a lower speed than the fixed signal, you must slow to the cab’s limit. If both indicate Stop, you stop. The other ideas don’t fit the standard rule: prioritizing the cab over the fixed signal would ignore track authority; following only the least restrictive indication would allow unsafe speeds or movements; and dispatcher instructions apply only when explicitly given, whereas the default safety rule is to heed the more restrictive indication.

When two signaling sources don’t agree, you operate under the more restrictive indication. This keeps you from exceeding a restriction shown by either system and prevents entering a block under a condition that’s more limiting than it appears.

In practice, cab signals provide in-cab speed and authority, while fixed signals give the track-side authority. If they don’t conform, you must follow the stricter instruction. For example, if the fixed signal shows a restrictive aspect or stop, you must obey it even if the cab indicates you may proceed. Conversely, if the cab shows a lower speed than the fixed signal, you must slow to the cab’s limit. If both indicate Stop, you stop.

The other ideas don’t fit the standard rule: prioritizing the cab over the fixed signal would ignore track authority; following only the least restrictive indication would allow unsafe speeds or movements; and dispatcher instructions apply only when explicitly given, whereas the default safety rule is to heed the more restrictive indication.