the opening of an in-system transfer passageway among the three stations. Additional out-of-system transfers are added on a case-by-case basis, usually whenever a regular transfer is unavailable due to construction. Past instances included two transfers in Williamsburg and Bedford–Stuyvesant, Brooklyn, due to the 14th Street Tunnel shutdown from 2019 to 2020; a transfer in Gravesend, Brooklyn, due to the BMT Sea Beach Line ()'s partial suspension from 2019 to 2020; and two transfers in Inwood, Manhattan, in 2019 due to the closure of the 168th Street station (). Transfer restrictions There are restrictions on transfers, as noted below. The transfer rules and restrictions are identical for MetroCard and OMNY, where OMNY is available. Bus For Pay-Per-Ride MetroCard and OMNY customers, there is no free transfer back onto the same route on which the fare was initially paid, or between the following buses: No transfer in the opposite direction (but transfers are permitted to buses in the same direction): M1, M2, M3, M4 M101, M102, M103 Bx1 and Bx2 No transfer in either direction: M96 and M106 Bx40 and Bx42 No transfers between NICE bus routes that are not listed on the timetable of the route on which fare is paid. Essentially, one cannot transfer between bus routes that do not intersect. Express: No transfers to/from BxM4C, even with a Pay-Per-Ride MetroCard. No transfers between different Union Turnpike express buses (QM1, QM5, QM6, QM31, QM35, QM36) traveling in the opposite direction. Between subway and bus There are no subway-to-bus or bus-to-subway transfers allowed without a MetroCard or OMNY, with one exception: At the Rockaway Parkway Intermodal Center on the BMT Canarsie Line (), westbound B6, B82 Local, and B82 Select Bus Service customers arriving from East New York and Canarsie, eastbound B6 Local customers on trips terminating at Rockaway Parkway, and all B42 customers, are transported directly into the subway system's fare control without having to pass through turnstiles (as the former trolley line had a loop installed within fare control). Similarly, subway passengers can transfer to B42 and westbound B6 and B82 Local service without using a MetroCard or OMNY (westbound B82 SBS customers must still obtain proof of payment, but have a second transfer to another route). NYC Ferry As NYC Ferry uses a separate fare payment system from the rest of New York City's transportation system, it does not provide any free transfers to any other modes of