What are the rules for China's visa-free transit programs?

I’m flying from Malaysia to Kazakhstan via Guangzhou and Urumqi in a couple of days. After emailing and calling China Southern, the Chinese embassy in Kuala Lumpur and the Chinese consulate in Kota Kinabalu, I still don’t have a definitive answer as to whether a visa is required or not. All of them said to get a transit visa “just to be safe”, which I’ve done now.

I interpreted Timatic the same way Coke did, but didn’t want to take any risks. I do believe “If Urumqi is the first transit point” are Coke’s words, because that doesn’t seem to be explicit on Timatic. I’ll update my post after the flights, if I learn anything more than stated already.

Edit: It turns out China Southern has a transfer lounge at Urumqi. When we arrived at 13h30, there even was a free lunch buffet. They seem to want to keep you here until 2 hours before the flight out of Urumqi. I assume this is to meet the 2 hour Transit Without Visa rule for Urumqi. In other words, I believe that a visa isn’t needed, as long as you apply for the TWOV at your first airport in China.

WARNING: Timatic has experienced a major overhaul. There are some inconsistencies, and I’m going to clear them up with my IATA contact, after which this answer will be updated.

The following is taken from Timatic, the database used by airlines (wording occasionally modified by myself to make it more understandable).

The following quotes address the question: who can transit without a visa, and under what conditions?

General restrictions:

• Transit without visa (TWOV) is not possible at Fuzhou
  (FOC), Huangshan (TXN), Mudanjiang (MDG), Shenzhen (SZX)
  and Yanji (YNJ).

• For transit without visa (TWOV) purposes, the USA territories of Guam or Northern Mariana Islands do not count as third countries in relation to the USA. Hong Kong, Macau and Taiwan, however, do in relation to China.

• Passengers with a
  British National (Overseas) passport
  must hold a Mainland Travel Permit for Hong
  Kong and Macao Residents (Hui Xiang Zheng, credit-card
  format) together with their Hong Kong ID

For Hong Kong/Macau/Taiwan passport holders

• Hong Kong/Macau passport holders

  Passengers holding
  confirmed onward airline tickets to a third country, in
  transit through Guangzhou (CAN), Shanghai Pudong (PVG) or
  Beijing (PEK), for a maximum transit time of 24 hours.

• Taiwan passport holders

  Passengers holding confirmed onward airline
  tickets to a third country, in transit through Beijing
  (PEK), for a maximum transit time of 24 hours.

If Urumqi is the first transit point

Holders of confirmed onward airline tickets, in transit
through Urumqi (URC), for a max. transit time
of 2 hours. Transit incl. multiple stops within China
(People’s Rep.), with a total transit time of max. 24 hours,
is permitted.

This does not apply to nationals of nationals of
Afghanistan, Azerbaijan, Hong Kong, Iran, Iraq, Kazakhstan,
Kyrgyzstan, Macau, Malaysia, Nigeria, Oman, Pakistan, Syria,
Saudia Arabia, Sri Lanka, Taiwan, Thailand, Turkey, United Arab
Emirates and Yemen.

In all other cases

• 24-hour rule (except at Guangzhou)

  Holders of confirmed onward air, cruise or train tickets for
  a max. transit time of 24 hours. Transit
  incl. multiple stops within China (People’s Rep.), with a
  total transit time of max. 24 hours, is permitted. They must
  travel to a third country.

  This does not apply to nationals of Malaysia with a normal
  passport in transit through Xiamen (XMN).

  Nationals of Canada and USA are not permitted to use the
  multiple-stop transit within China, if transiting through
  Weihai (WEH) or Wuhan (WUH).

• 24-hour rule (at Guangzhou)

  Holders of confirmed onward air tickets in transit through
  Guangzhou (CAN) to a third country, for a max.
  transit time of 24 hours.

  This does not apply to nationals of Syria.

  Transit incl. multiple stops within China (People’s Rep.)
  is permitted at Guangzhou (CAN) only when the first transit
  point is Beijing (PEK). The total maximum transit time is
  24 hours.

• 72-hour rule

  Nationals of Albania, Argentina, Australia, Austria,
  Belarus, Belgium, Bosnia and Herzegovina, Brazil, Bulgaria,
  Canada, Chile, Croatia, Cyprus, Czech Rep., Denmark,
  Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
  Ireland (Rep.), Italy, Korea (Rep.), Latvia, Lithuania,
  Luxembourg, Macedonia (FYROM), Malta, Mexico, Monaco,
  Montenegro, Netherlands, New Zealand, Poland, Portugal,
  Qatar, Romania, Russian Fed., Serbia, Slovakia, Slovenia,
  Spain, Sweden, Switzerland, USA, Ukraine, United Arab
  Emirates and United Kingdom holding confirmed onward airline tickets departing
  directly to a third country, if arriving in and departing
  from the same city:

  • Changsha (CSX), Chengdu (CTU), Chongqing (CKG), Dalian
    (DLC), Guangzhou (CAN), Qingdao (TAO), Wuhan
    (WUH), Xi’an (XIY) or Xiamen (XMN) for a max. transit time
    of 72 hours, starting from 00:01 on the day following the
    day of entry.

  • Guilin (KWL), Harbin (HRB), Kunming
    (KMG), or Shenyang (SHE) for a max. transit time of 72
    hours;

• 144-hour rule

  Nationals of Albania, Argentina, Australia, Austria,
  Belarus, Belgium, Bosnia and Herzegovina, Brazil, Bulgaria,
  Canada, Chile, Croatia, Cyprus, Czech Rep., Denmark,
  Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
  Ireland (Rep.), Italy, Korea (Rep.), Latvia, Lithuania,
  Luxembourg, Macedonia (FYROM), Malta, Mexico, Monaco,
  Montenegro, Netherlands, New Zealand, Poland, Portugal,
  Qatar, Romania, Russian Fed., Serbia, Slovakia, Slovenia,
  Spain, Sweden, Switzerland, USA, Ukraine, United Arab
  Emirates and United Kingdom, holding confirmed onward air, cruise or train
  tickets to a third country, arriving in and departing from
  any one of the following locations (same region required) for a maximum of 144 hours, starting from 00:01 on the day following the day of entry.:

  • Region A: Beijing (PEK), Tianjin
    (TSN), Shijiazhuang (SJW), Beijing West Railway Station,
    Tianjin International Cruise Home Port, Qinhuangdao Sea
    Port

  • Region B: Hangzhou (HGH), Nanjing Lukou (NKG), Shanghai Hongqiao (SHA), Shanghai Pudong (PVG), Shanghai Port International Cruise Terminal, Shanghai Wusongkou (Baoshan) International Cruise Terminal, Shanghai Railway Station