Hamilton square, Liverpool Central stations
At a guess the worst section on Merseyrail is the stretch between Green Lane and Birkenhead Central, with sharp reverse curves.
Birkenhead Central platform itself isn't quite as bad, however.
Many of these sharp curves are the result of joining up a pair of previously straight routes, converging nearly at right angles.
That's why Earlestown and Bristol TM got their curves, also York.
The Warrington & Newton was initially laid out with a junction facing Liverpool at Earlestown, and the sharper Manchester curve was put in later as an afterthought.
It's the same a short distance away at Parkside, where the easy junction for the Wigan Branch Railway facing Manchester was put in first, and the much tighter Liverpool curve much later (through the sharply curved Lowton station).
The LNWR eventually built the Winwick-Golborne cut-off on the WCML to avoid the two sets of slow curves.
At Bristol, the curves joined the original GWR to the Bristol & Exeter, and at York they joined the York & North Midland to the York & Newcastle.