I have searched around through multiple sources in an attempt to get somewhere close to accurate information. Here it is for what it is worth:
General:
The line is not a dedicated high speed railway, but a mixed purpose new line.
China’s railways operate left-handed despite driving on the right-hand side of roads.
Three railway officials were fired immediately following the accident.
Damaged equipment has been removed, either to Wenzhou South Station or other sites not given.
The line was returned to service on July 25.
Premier Wen Jiabao has promised a full investigation.
The true cause and cascade of events leading to this collision is unlikely to ever be clearly explained, despite the statement made by the Premier.
The line:
The line is known as the Yongtaiwen Railway. It opened on September 28, 2009 between Ningbo East and Fuzhou South, 564 km (350 miles). By rail, Ningbo is 333 km (207 miles) south of Shanghai. The line is double track, designed for mixed traffic operation and a maximum passenger train speed of 250 km/h (155 mph). (From timetables and the Railway Gazette)
Track: Track is ballasted track, including on long viaducts (based on pictures)
Train Control System: The line is equipped with lineside signals overlaid with CTCS-2 to provide automatic train protection. This has a similar functionality to ETCS Level 1, using balises to provide intermittent updates to the on-train equipment. (Source: Railway Gazette)
Equipment: (from the Railway Gazette and elsewhere)
Train D3115: The first train, running Hangzhou to Fuzhou. 16-car CRH1-046B EMU
Train D301: The second train, running Beijing to Fuzhou. 16-car CRH2-139E EMU
Passenger loading: 1072 passengers on D3115 and 558 passengers on D301
Accident location:
The collision occurred about 4.9 km (3.1 miles) north of Wenzhou South Station. At this location the track is on a 15 to 20 meter (50 to 65 feet) high viaduct located between the crossing of the Oujiang River and a short tunnel through Daping Mountain. (From accident scene photographs and Google maps and aerial views)
Wenzhou South is 270 km (168 miles) south of Ningbo East. (Enter the railroad station name into Google maps and work north along the railroad and you can find the location in the sattelite view that matches the surrounding seen in aerial shots of the accident)
Pre-accident events and chronology:
The description and chronology of events leading up to the collision are given by multiple sources, not all of which are in agreement or compatible with each other.
The time of the collision was 8:30pm Saturday July 23, 2011 local time, give or take a few minutes. (This is 8:30am Saturday July 23 US Eastern Time.)
That lightening struck train D3315 as some sources stated, appears to be incorrect. Whether by lightning strike or other cause, there was a signal and train control system failure or malfunction on the northern approach to Wenzhou South, the length of affected area not clearly stated.
The Railway Gazette states, "…train D3115 between Hangzhou and Fuzhou had apparently been brought to a stand by a lightning strike further along the line. Around 20 min later it was hit from the rear by Beijing – Fuzhou train D301…"
From the China Daily of July 28, 2011: "After being struck by lightning, the signal system at the Wenzhou South Railway Station failed to turn one of its green lights to red, which caused the rear-end collision, said An Lusheng, head of the Shanghai Railway Bureau, at an investigatory meeting held by the State Council, or China's cabinet, in Wenzhou."
A more detailed and also fairly reasonable scenario was found, but it does not agree with the statement in the Railway Gazette and elsewhere that train D3115 was stopped for 20 minutes.
This scenario is as follows:
Time _ Event
19:39 - Signals near Wenzhou South were found to be malfunctioning, all showing red.
19:51 - D3115 arrived at Yongjia (18 km [11 miles] north of Wenzhou South) 4 minutes late
19:53 - A decision was made that the signals were to be over-ridden and manual operation commenced controlled from the Wenzhou South control center
19:55 - Manual operation commenced from Yongjia control center
20:06 - D301 was informed of manual operation and made an unscheduled stop at Yongjia at 20:12 (this would make it approximately 38 minutes late)
20:15 - D3115 departed from Yongjia 27 minutes late, instructed to run past red signals at 20 km/hr (12.4 mph)
20:22 - D301 was given the clear to proceed
20:23 - D3115 reached the start of signal failure area and stopped
20:24 - D301 departed from Yongjia at high speed, with his signals all showing clear (9 minutes after the departure of D3115. This would make it approximately 50 minutes late)
20:25 - D3115 began running towards Wenzhou South at 20 km/h
20:30 - D3115 driver reported a passenger operated emergency stop, unaware that the stop was because his train has just been rear-ended.
Discussion:
Assuming an approximate 4.0 minutes run time for the 4.9 km between the accident point and Wenzhou South Station, at the time of the collision train D3115 would have been 37 minutes late and train D301 would have been 46 minutes late.
Assuming the times in the above chronology are correct, the average speeds over the 14 km between Yongjia and the collision point were:
Train D3115, 15 minutes = 56 km/h = 35 mph
Train D301, 6 minutes = 140 km/h = 87 mph
At impact the train speeds were:
Train D3115: either stopped or 20 km/h, with 20 km/h being more likely.
Train D301: variously reported as being "around 90 km/h" to "very high."
Upon impact, train D301 rode up over the top of train D3115. All cars off the bridge were part of train D301. All cars of train D3115 remained on the structure, with the last car significantly damaged and the top crushed in. The next to last car had significant damage.
The first 3 cars of train D301, including the driving car went completely off the structure to the ground. The fourth car ended up on end leaning against the structure at an angle of about 15 degrees from vertical. The fifth car of D301 stopped about half over the top of the last car of train D3115. This indicates a stopping distance of about 110 meters (360 feet) for train D301.
Injuries and fatalities:
Based on the July 28 article in the China Daily reporting Premier Wen Jiabao’s site visit, the official toll has become set at 39 deaths and 192 injuries. These numbers are likely to be significantly understated given the obvious equipment damage and the reported passenger loading. This understatement is probably deliberate since it has been reported that the word has come down that official pronouncements are not to be questioned.
Other information:
The accident site was on a viaduct between the Oujiang River and Wenli Expressway to the north and a short tunnel is through the spur of Daping Mountain to the south. Wenzhou South Station is beyond the mountain. There are a sufficient number of unique features to enable precise determination of the location on Google Maps which also enabled the distance from this point to Wenzhou South station to be scaled.
Train schedules can be found on www.chinatrainguide.com/schedule/
enter station names or train numbers to find whatever information you want
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