Instead of D2, build a downtown transit loop (ala Chicago). DART will now consist of a loop with seven trains running off of it. Each train would come in from their respective route, circle downtown on a double track, and then proceed back out the way it came. People interested in going across town would simply transfer at any stop.The loop would follow the corridor we have now but will also turn east after/before the Convention Center stop and follow (above, next to) 30 to the 345 ROW. It would then go north along 345 to Good Latimer where it will connect with the green line portion.Because every train would be heading in the same direction (either clockwise or counter-), they could use both sets of tracks, effectively doubling the capacity of the current transit mall.