Traffic congestion and trucking activities in the San Francisco Bay Area are increasing due to the rapid population growth and economic expansion. It is imperative to explore transportation alternatives, and the Bay Area Rapid Transit (BART) system, with 63 percent unused capacity on average in non-peak hours, presents such an opportunity. If BART’s service is extended to include air-freight movement, extra revenue can be generated, truck miles travelled on highways will be reduced (potentially leading to a reduced traffic congestion and pollution), and traffic safety could be improved. The objective of this study is to identify the number of feasible dedicated freight train that can be accommodated by BART lines using its current operational schedule, without creating a negative effect on passenger service. The measurement of time or distance between two successive train-runs at a station, also referred to as the ‘headway’, for selected lines have been considered to evaluate possible freight train insertions into time-space slots of current passenger services. To qualify this, the headway of the two trains needs to be greater than twice the minimum headway required (based on BART train safety requirements). Furthermore, BART trains should be subjected to the limit on acceleration/deceleration capabilities. The findings are as follows: for peak hours and commute directions, it would be impracticable to add more trains. For peak hours in non-commute directions, some capacity could exist for mixed freight cars and on empty passenger cars. For non-peak periods such as early mornings and evenings, slots for dedicated freight train insertions are available.