I'm making this fictional route, North Express Line (NXL), which
involves 4 stations, Boon Lay, Sembawang, Sengkang, and Changi
Airport.
Train used will be C251 (hehehe, I made this), which will be a
varient of C751A and have a max speed of 150 km/h. :D
Description: The route starts at Boon Lay, elevated with 3
tracks (the middle track being a standby track), and will merge
after the train leaves the station. Right after the merge there'll
be 2 crossovers so that the train can switch tracks. The train will
now travel northwards at high speed towards Sembawang. The tracks
will cross above the NSL tracks. Right after Sembawang there will
be a reverse sliding in the middle of the main tracks, which is
able to hold 6 cars at one time. After the reverse sliding the
tracks will cross above the NSL tracks again. The tracks will
travel will street level along TPE some time before arriving at
Sengkang, and the train will travel down into a tunnel leading to
the station. After Sengkang the route will be fully underground,
where there'll be a bunch of crossovers leading to Sengkang Depot.
After a distance there'll be a crossover right before Changi
Airport station. The platforms will be right below the existing EWL
platforms.
The elevated stations will have half height PSDs and the
underground ones with full height PSDs.