thumb|From 29 August 2021, Line 1 trains began to run Batong Line
thumb|Two Batong line trains at [[Guoyuan station before renovation]]
The Batong Line of the Beijing Subway () is an east–west rapid transit line in eastern Beijing. It extends Line 1 further east from in Chaoyang District to in Tongzhou District. Through operation with Line 1 started on August 29, 2021. and runs
Route
The Batong Line follows the Beijing-Tongzhou Expressway eastward from Sihui to Guǎnzhuang. Between Gaobeidian and Guǎnzhuang, the Batong Line and its stations are built into the highway's median. At Bali Qiao, the Batong Line turns to the southeast and follows the Jingtang Road to Tu Qiao, which is located just inside the Tuqiao Bridge exit on the eastern 6th Ring Road. From there, the line turns and follows the 6th Ring Road south and west to and .
Stations (from West to East)
Station list for Line 1 and Batong line of Beijing Subway, after the through operation started on August 29, 2021. However, during peak hours sections the line still operates above 100% capacity. The extension is 4.5 km in length, including 3.8 km underground section. station was opened on December 28, 2019.
Opening timeline
{| class="wikitable" style="border-collapse: collapse; text-align: right;"
!Segment!!Commencement!!Length!!Station(s)!!Name
|-
|style="text-align: left;"| Sihui — Tuqiao
| 27 December 2003
|
| 13
|style="text-align: left;"| Phase 1
|-
|style="text-align: left;"| Tuqiao — Huazhuang
| 28 December 2019
|rowspan="2"| However, the Beijing Subway responded that Line 1's and Batong's signal systems are completely different, so through-operation will be more difficult to achieve from an engineering standpoint. As of 2016, preliminary design and feasibility studies are underway to allow for through operations between Line 1 and Batong. On June 12, 2020, the project of the through operation of Line 1 and Batong line was approved by Beijing Development and Reform Commission. Through operation with Line 1 started on 29 August 2021.