If you are colorblind (to any degree), the new London map is very difficult to see. In fact the only two lines I could easily tell apart were the yellow and blue. Every other line is so similar looking I found myself moving wrong lines and moving trains to the wrong line. Not to be hyperbolic, but I dont think you could have chosen worse colors for colorblind people especially the first 2 whixh look identical to me. I deleted the first line after I duplicated it with the yellow one. 8% or more of all males are colorblind which is a substantial number of people who cant play this map
I’m so sorry that you are having difficulty with the new map. The accessibility of all users is definitely something that we strive for.
I can believe that the Old London colours would be terrible for any colorblind users as they are quite similar. However, could you confirm that you have colorblind mode enabled in the options menu? We specifically catered those colors to be as distinct for as many people as possible.