Beijing–Ulaanbaatar International Express (K23/K24)

China Railway (CR Beijing / CR Hohhot) and Ulaanbaatar Railways (UBTZ)
China
Mongolia
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The Journey

Navigate from Beijing Railway Station (北京站) to Ulaanbaatar Railway Station (Улаанбаатар Өртөө) across a span of 1553km. This is an overnight service.

Scenery Highlights
  • Glancing views of the Great Wall as you leave Beijing
  • Inner Mongolian grasslands between Jining South and Erlian
  • Endless ochre dunes of the Gobi Desert
  • Wide-open Mongolian steppe and big-sky sunsets after the border
  • Bogie-change theatre at Erlian / Zamyn-Üüd — one of rail travel's great practical spectacles
Quick Facts
  • Duration

    31.1 hours

  • Distance

    1553 km

  • Est. Price

    Approx. CNY 1,518 hard sleeper / CNY 2,273 deluxe soft sleeper one way Beijing–Ulaanbaatar (K23) booked via 12306 or CITS; K24 Ulaanbaatar→Beijing typically CNY 1,110 soft sleeper / CNY 990 hard sleeper (MNT pricing). International agency markup from US$230–360 per person typical.

Official Booking Provider
Classes & Accommodations

Meals: None (restaurant car available for purchase)

Ensuite: No

Meals: None (restaurant car available for purchase)

Ensuite: No

Engine / Locomotive

Diesel-electric locomotives; CR HXD3C electric from Beijing to Jining South, then CR DF4D diesel to Erlian; UBTZ CKD4B diesel from Zamyn-Üüd through Mongolia

Locomotive Weight

HXD3C electric locomotive ≈ 92 t; CR DF4D diesel ≈ 138 t; UBTZ 2M62(M) and 2TE116 diesels ≈ 120–180 t each

Track Gauge

1,435 mm standard gauge (China) / 1,520 mm Russian broad gauge (Mongolia) — gauge break at Erlian / Zamyn-Üüd, with full train bogie exchange

Braking Technology

Compressed air brakes; automatic knuckle couplers; dual braking regime change at the border

Route Engineering Challenges

  • Gauge break at border: entire train is jacked up and bogies swapped (1,435 mm → 1,520 mm) — a process of approximately 3 hours that passengers watch from the carriage

  • Dual-gauge operation requiring different braking regimes and rolling stock on each side

  • Extreme temperature range: −40 °C winter to +40 °C summer across the Gobi and steppe

  • Long distance across sparsely populated terrain requiring crew change and rest facilities at Jining South and the border

  • Sustained crosswind exposure on the open Mongolian plateau

Operator

China Railway (CR Beijing / CR Hohhot) and Ulaanbaatar Railways (UBTZ) joint service

Route distance

1,553 km Beijing–Ulaanbaatar

Maximum speed

120 km/h (China), 100 km/h (Mongolia)

Carriage type

CR 25G Chinese sleeper cars (CN section) + UBTZ Mongolian sleeping cars (MN section)

Crew change

Chinese crew Beijing–Erlian, Mongolian crew Zamyn-Üüd–Ulaanbaatar

Border stop

Erlian / Zamyn-Üüd: ~3 hours for immigration, customs and bogie exchange; passengers remain on board

Resumed service

Cross-border K23/K24 service resumed June 2025 after a multi-year pandemic-era suspension

Quick Facts
  • Duration

    31.1 hours

  • Distance

    1553 km

  • Est. Price

    Approx. CNY 1,518 hard sleeper / CNY 2,273 deluxe soft sleeper one way Beijing–Ulaanbaatar (K23) booked via 12306 or CITS; K24 Ulaanbaatar→Beijing typically CNY 1,110 soft sleeper / CNY 990 hard sleeper (MNT pricing). International agency markup from US$230–360 per person typical.

Official Booking Provider