Nanzoin (南蔵院) is a Tendai Buddhist temple located on the northeastern outskirts of Tokyo, which is a 16-minute walk from JR Joban Line Kanamachi Station or Keisei Kanamachi Line Keisei-Kanamachi Station. This temple is not so large but known for Shibarare Jizo. Shibarare Jizo is a stone statue of Jizo Bosatsu tied thickly with ropes.
From 11pm on New Year's Eve, the temple monks do nawatoki (縄解き), or untying of the ropes binding Shibarare Jizo. From 0AM, firstly monks, and then ordinary people attending the ceremony, bind it again with new ropes (縄かけ). While this ceremony is going on, Gagaku music is performed.

Nawatoki Kuyo and Hatsu-Nawakake

From around 11:30pm on New Year's Eve, the ceremony begins. It will be as follows.

A few stalls were set up beside the main gate.

From around 11:30pm, gagaku (a kind of traditional music) is performed.

Temple priests head for Shibarare Jizo.

Shibarare Jizo is covered with ropes completely.

The head priest of the temple untie the ropes with help of assistants and uncover Shibarare Jizo, which is a stone statue erected in 1701.

After unbinding the ropes completely, the priests go to the adjoining Jizodo, the hall enshrining Jizo Botsu, to do some rituals.

First, the head priest rings the huge bell, followed by ordinary people. This ritual, which is called Joya no kane, is a custom widely practiced throughout Japan. If you, too, want to ring the bell, get the tickets (free of charge) being handed out from 10pm.

When New Year arrives, the head priest bind Shibarare Jizo with a rope.

Then ordinary people follow to tie the statue.

At this point, there are three lines of people in the precincts: One people wanting to tie Shibarare Jizo, one people trying to ring the bell, and one people waiting to do hatsumode to Jizodo. It was about 0:20am.
Hatsumode is also a popular custom across Japan, which people pay their first prayers of the year to Shinto shrines and some Buddhist temples.

About trains

From 0am to 5am on Jan 1st, though the JR Joban Line is operating all night, trains are sparce. On the other hand, the Keisei Kanamachi Line is running every 20 to 50 minutes between Keisei-Kanamachi Station and Keisei-Takasago Station. At Keisei Takasago Station, trains heading for either Narita, Ueno, or Oshiage (the trains bound for Oshiage are connected directly to the Toei Asakusa Line) are running every 20 to 50 minutes.