There is no railway parallel to the closed section. There's a bus route.

When we carry out transfer transportation by route bus (municipal, private management) parallel to municipal subway, we will guide you by broadcasting in the same way as in other railway companies. Please show your ticket at the municipal subway station window and receive a transfer ticket.
By bus, please put your ticket and transfer ticket in the fare box. Passengers who use commuter passes and customers who continue transfer transportation are required to put only the transfer boarding slip in the fare box and present the commuter pass or ticket.
The latest information on transfer will be transmitted to bus crews by radio from the sales office. In rare cases, the latest information may not be transmitted to bus crews due to radio conditions or time gaps, but please tell the bus crew that transfer transportation is being carried out. The bus crew will check with the sales office.
If you want to take more than one route on the transfer section, please get necessary number of sheets as much as possible. If only one ticket is issued, please inform the crew of that fact and show your ticket before boarding. If you are unable to receive a transfer ticket due to the absence of station staff, please present your ticket or commuter pass to the crew and offer that it is a transfer.

Transfer of Municipal Subways

What is Transfer Transport?
What is the response when a municipal subway stops driving due to an accident or the like?
What should I do with the ticket gates of other railway companies when using transfer transportation?