R142a 4 Bronx Expres

Lol what I'm trying to say is why would the 4 line lose its R142As if it only run a few of them compared to the 6.

I think the Westchester yard is going to lose their R142As to the Corona yard, the 4 train needs its R142As for yankee games since it has wider doors than the R62a.

And are the new r188 trailer cars going to have one motorized truck per car or both trucks are going to be motorized