I'll just say that one thing we really need is redundancy in the system, for when trains break, things need to get closed for prolonged maintenance, etc. Having the CR redundant on the OL in the South and Braintree branch makes all of those things way more bearable for riders. On the Ashmont line, I have certainly been jealous with the only real option for me is shuttle buses which are not ideal. I'd argue is one of NYC's biggest assets in their system is how much redundancy is built in, especially the core where lines can be rerouted onto other lines if if they needed. 6th Ave subway needs to be completely shutdown? Well, you have 1 block away the 8th and 6th ave subways. Need to close the 53rd st tunnel to Queens? Just reroute to either the RI tunnel or 60th st which are all reasonable close and get you where you need to be on the Queens Side.