This paper elaborates a model for representing various types of semantic calendar expressions (SCEs), which correspond to the disambiguated intensional meanings of natural-language calendar phrases. The model uses finite-state transducers (FSTs) to mark denoted periods of time on a set of timelines also represented as an FST. In addition to an overview of the model, the paper presents methods to combine the periods marked on two timeline FSTs into a single timeline FST and to adjust the granularity and span of time of a timeline FST. The paper also discusses advantages and limitations of the model.