Accident or terrorism?

LAHORE: The authorities, army and Railways sources do not rule out terrorism as the cause of troops train tragedy.
The railway track on the Head Chanawan Bridge in Jamke Chattha is a part of the Wazirabad-Faisalabad railway line. This track is used by only one passenger train — the Pakistan Express that operates between Rawalpindi and Karachi.
Both Railways Minister Khawaja Saad Rafique and the Inter Service Public Relations (ISPR) DG have hinted that this could be an act of terrorism targeting the military.
Noteworthy is the fact that the Pakistan Express had passed through the same Head Chanawan Bridge 45 minutes before the special train carrying the army personnel and freight. The Pakistan Express was loaded to capacity and yet had no issues whatsoever.
However, as soon as the engine of the special train came almost to the middle of the bridge, it apparently collapsed either right under the engine or at the section of the bridge in front of the moving engine. The rationale behind this calculated assertion is that had the bridge collapsed due to the load of the freight or the bogies, it would have collapsed behind the engine, not in front of it.
The state of the crashed engine too is a question mark in itself. It appears to have virtually snapped into two pieces. There can be two plausible explanations for such an eventuality.
One could be the head-on impact of the diving engine with the pillar of the bridge. This could result in the event of a total drop of a section of the bridge in front of the engine. The second could be in the event of an explosion either right under the engine on the track or inside the engine which damaged the engine and the bridge, causing the fall into the canal.
The initial investigation and the information gathered from the locals revealed that they did not hear any major explosion which apparently rules out the possibility of the track on the bridge or the engine being blown up through explosives.
In the event of the track fishplates being tampered to a point that it led to the collapse of the bridge, the engine would have fell into the canal face up instead of a nosedive. Had this been the case, the state of the damage to the engine cannot be explained as it is, as it clearly impacted with the bridge on a nosedive.
Also, tampering with fishplates that had been installed years ago is not a task that can be accomplished in a matter of minutes. The rivets of these plates become increasingly locked over period of time and load that they take. These fishplates, therefore, would have been tempered with within the time 'Pakistan Express' crossed the bridge and the special train arrived. Had they been tempered with earlier, the Pakistan Express would have suffered this accident. This also in a manner hints at the train carrying the army personnel being a specific target.
Therefore, there can be is only one plausible theory which makes sense regarding this unfortunate loss, which justifies and compliments all the circumstantial evidence gathered so far. This hypothesis is the probable demolition of one of the pillars of the Head Chanawan Bridge "underwater".
In this case, nobody would have heard the explosion as it was underwater. It would have caused an entire section of the bridge supported by that pillar to fall down.
The collapse of the bridge section in front of the moving engine would have made it to take a nosedive straight into the next pillar of the bridge causing the massive damage to the engine due to its momentum of the passenger and freight bogies behind it.
In any of the possibilities discussed, it would be difficult to track what had exactly happened because there was 8,700 cusec water discharge in the canal at the time of the incident which would have easily washed away the evidence of explosives, if any, and the debris. The underwater nature of the explosion would have muffled the explosion.
An underwater explosion, although is muffled yet due to water being a denser medium than air, the shockwave is stronger and can damage more.
The assistant driver of the special train, after recouping from in the hospital, told media that he felt a very strong vibration right before the train fell into the canal. This strong vibration could have been the shockwave generated by the underwater explosion transmitted through the water to the entire concrete structure of the bridge.