Are you intending to use the off-the-shelf latching relay module from Azatrax (or the like)… or cobble together the latching function using a multi-relay non-latching eBay relay module as shown in my diagram? I may have misunderstood you previous response but I thought you were going with the Azatrax method.
The diagram I showed with ZWC and so on was just a cut-and-paste from the other thread with a similar but not quite the same trolley configuration. That version required delay modules and so on. Your application is simpler and does not require delay modules. I can draw up a diagram for your specific trolley application. So,
1. Which latching relay method are you planning to use?
2. What is your power source/transformer?