Yeah absolutely! A local service that works well alongside a high speed intercity one would be greta, though may be better to build after the main route (don't want some small stations slowing down the main route build).
For the East/West corridor slower speed trains at the same stations allowing transfers would be preferable (cheaper and quicker to build, with minimal speed impact) to high speed rail.
For the East/West corridor slower speed trains at the same stations allowing transfers would be preferable (cheaper and quicker to build, with minimal speed impact) to high speed rail.