  Observations with the current generation of very-high-energy gamma-ray
telescopes have revealed an astonishing variety of particle accelerators in the
Milky Way, such as supernova remnants, pulsar wind nebulae, and binary systems.
The upcoming Cherenkov Telescope Array (CTA) will be the first instrument to
enable a survey of the entire Galactic plane in the energy range from a few
tens of GeV to 300 TeV with unprecedented sensitivity and improved angular
resolution. In this contribution we will revisit the scientific motivations for
the survey, proposed as a Key ScienceProject for CTA. We will highlight recent
progress, including improved physically-motivated models for Galactic source
populations and interstellar emission, advance on the optimization of the
survey strategy, and the development of pipelines to derive source catalogues
tested on simulated data. Based on this, we will provide a new forecast on the
properties of the sources thatCTA will detect and discuss the expected
scientific return from the study of gamma-ray source populations.
