Complex sentence: As a result, trains will be unable to use this tunnel segment; however, the MTA suggests that the tunnel segment could be used to store ancillary facilities for the subway line, such as a power substation or a ventilation facility.
Split into simpler sentences: As a result, trains will be unable to use this tunnel segment. However, the MTA suggests that the tunnel segment could be used to store ancillary facilities for the subway line, such as a power substation or a ventilation facility.