Term:E-Stop

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eSTOP or Emergency Stop is a special speed step defined in the NMRA Digital Command Control Specifications.

For more information see the page on DCC Packets.

E-Stop Command

Inside the DCC Packet is a set of bits reserved for speed step information. If all of the bits are set to a value of zero (0000 for 28 and 14 speed steps) the addressed decoder moves to the stop position.

If the Least Significant Bit is set to one (0001), the value is the eSTOP command. eSTOP is a Broadcast command, meaning that all decoders will immediately change to STOP and all moving trains halt.

By pressing the Emergency Stop button on your throttle the command station generates a broadcast packet with the eSTOP command and that is immediately transmitted tot he booster and onto the rails. Everything in motion will immediately stop.

Note
The E-Stop command does not disconnect power to the rails. A valid DCC signal remains. Any mobile decoders set to allow Analog operation could be set their locomotive in motion by a corrupted DCC signal, and may not respond to the E-Stop command

Further Reading

See the pages on Speed Steps and DCC Packets for more background on the NMRA DCC Standard.