Observations with the current generation of very-high-energy gamma-ray telescopes have revealed
an astonishing variety of particle accelerators in the MilkyWay, 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 Science
Project 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 that
CTA will detect and discuss the expected scientific return from the study of gamma-ray source
populations.