The BM2 lets an external signal control a block section. Both stop and slow approach are supported. The BM2 can also be used as the last section of of a BM3 block management chain and/or used as a block occupancy detector and connected to an LR101.
The Quantum Engineer allows DC Analog users to access up to 28 sound decoder functions, but alone doesn't quite have enough current capacity for large scale locomotives. Use the Quantum Engineer Booster to get up to 40 Amps of DC power for your large scale multiple locomotive consists and lighted passenger trains.