Yes, The Engine coupler electronically opens when you press the uncouple button, but they are mechanically closed by the slight force when bumped together.
Because your rolling stock has the mechanical couplers that open or close with an uncoupler track, your engine coupler may be open, but the rolling stock is closed. This makes it harder to get the engine to mechanically close on the rolling stock coupler because the alignment needs to be perfect.
I usually manually open the rolling stock coupler with my hand, then you can back the engine into the rolling stock and both couplers close.
The alternative is to drive the consist over an uncoupler track to release the rolling stock mechanical coupler. Once the engine pulls away you can open it's coupler electronically. When you want to pick the rolling stock back up, just back the engine into the rolling stock and they should recouple.
You need to find the right speed that locks them with out causing a derailment. Do it several times in a straight section in front of you and you will see how it goes and get the hang of it. G
