Kadee 308
Delayed 'under-the-track' Uncoupler 308

Under the track "hidden" installation. A permanent magnet and steel intensifier plate are included along with instructions. 
Suitable for a variety of scales from HO to O-Scale.
1 pc

Delayed Magnetic Uncoupling®
1. Stop with the couplers over an uncoupler and back up slightly with the couplers still over the uncoupler, allowing slack to occur between couplers.

2. Pull forward bringing coupler off the uncoupler. Couplers will snap to the delayed position.

3. Back up, pushing the car(s) to the desired location. Do not permit slack to develop between couplers.

4. Pull forward, leaving the car(s) where desired. Couplers will automatically return to normal coupling position.

https://www.youtube.com/watch?v=A51sBEm6VFA