There's however a big difference in double track in the station and double tracking the complete branch. If 4 trains an hour can be achieved with the existing single line, a longer passing loop, platform extensions for larger trains and no expectation of considerably more passengers. Looks like a good improvement to me.The business case linked in #729 narrowed it down to two options, both including double tracking at EK station.
The article linked in #801 suggests the last sentence may be out of date, and four trains per hour may be possible with most of the present single track remaining single.