If you are coming out of 3 on the up chances are you arent going to get much above 40mph anyway so its moot. Any faster and a new crossover may not have fitted. Anything on the down into 4 or 5 would likely be facing a red so again not a lot of benefit.
Its 75mph through the station, and flashing yellows on the approaches. You might get 10-15 seconds on a good day. Lots of money and disruption for naff all really. Lancaster got remodelled to an extent within the last 8-9 years anyway.