I'm not really sure what you mean by a time delay neutral. I've heard of solid neutral, a switched neutral, and overlapping neutrals.
Time Delay Neutral is with the transfer switch not connected to either source. The transfer switch would have 3 positions, source 1, neutral, & source 2. After a preset delay not connected to either source it would transfer to the good source or back to the preferred source.
Load Decay may be an option. The transfer switch monitors the load bus and transfers when the voltage on it decays to a preset level.