PARKCHESTER - Bronx commuters are bracing for partial closures on the No. 6 line at the Parkchester train station. The MTA has temporarily discontinued northbound service because of ongoing repairs. Bronx residents traveling north on the No. 6 line will have to get off at the Saint Lawrence station and take a bus or get off at the Castle Hill stop and then ride back down. The repairs are expected to continue until July 5.