the problem with approaching a platform is in the way it works.
As you know you have to set 'drive to xxxx' and then 'load' to make it work.
The problem is with the drive to command. the destination of this drive to command is the start of your station, not the end (where your train is supposed to stop).
When a train approaches it will go to the
beginning of your platform and reduce speed to prepare a stop as soon as it is there. Only after this, the 'load'-command takes control and makes the train go further on until the end of the platform. Because this distance is not long enough, it will not speed up, drive fast, then slow down and stop, but keep the low speed all the time.
You can try to work around this problem using a trackmark and command your driver to go there instead of the station. Then you must not use 'load' command but a third party one like 'stop train'. So the train is not aware of the drive to command and the beginning and end of the platform but only of your trackmark.
The other way is to use third party stations and third party commands like 'call at'-command.
Keep in mind: Yellow and Red signals, as well as end of line, sharp turns, wyes etc. will reduce the speed of your train,
even if they are just behind the station. Therefore you might want to consider
'Sometimes 35 is faster than 60'