OPRRMS' comments in italics
Holly Gibson's responses in regular font
Quotations from third parties in boldface

Both the DigiCon download and field download indicate it wasn't.

So we're subscribing to the theory that all of this hardware and software is 100 per cent fail safe and never can offer misleading information?

Here's an interesting comment or two from an electronics engineer culled from a discussion of this topic from TRAINORDERS.COM:

On the other hand, having worked as an electronics engineer for over 20 years, it seems well within the possibility for a signal system to malfunction in a way that is not easily repeatable by investigators. The likelihood for weird anomalies is directly proportional to the number of microprocessors used to make the system work. There are many times when the old, tried and true, electro-mechanical systems are superior, but are not used due to cost.

. . . and this . . .

As a retired electronics engineer myself, I fully agree with the potential for weird anomalies occurring under rarely seen and difficult-to-reproduce conditions in digital systems, especially when they are software driven. In fact a NASA bulletin i used to get at work had an extensive article about the impossibility of ensuring that complex software is fail-safe. And I'm also aware of a situation in which a false clear signal was found in a relatively recent signal installation under an unusual specific set of conditions that WERE reproducible, so yes, it happens.

However, it was explained to me that the event recorders that log signal aspects in the type of signal at Chatsworth actually sense current in each bulb. In that case, if the record indicates that at the time of the accident the red bulb was drawing current and the green one wasn't , and subsequent tests indicated that the recorders were functioning properly, I have to conclude that it is much less likely that such a fault could have occurred and not been detected. Maybe there's something I'm not understanding here, and the relationship between the recorder and the signal bulb isn't as simple as I was led to believe.

It certainly will be interesting to see what the NTSB report makes of the apparent conflict between the event recorders and the witnesses. While I'm not ordinarily inclined to feed theories about cover-ups and conspiracies, and while it's normal procedure for railroads (or any corporations) to gag employees about discussing accidents with the press, all this leaves me wondering if all the facts have been made public. The situation involving the apparently forced resignation of Metrolink's spokeswoman following a premature announcement about this accident that was supposedly approved by upper management, when combined with this apparent inconsistency, makes me more suspicious than usual that something here is not right.

That said, there can be no argument that the Dual Control switch at CP Topanga was lined in the reverse position for the Leesdale to enter the siding, since it showed obvious damage from being run through by Metrolink 111.

I'll agree with you on this one. I think it's pretty much a slam-dunk that the switch was not lined in favor of Metrolink 111. But, if the signaling system is royally screwed up, you could conceivably have some switch points not lined in your favor but also have a false clear signal indication lining you through that control point. In other words, if things are screwed up royally enough, all bets are off.

The position of the switch would be obvious to anyone in the cab who's paying attention. If I encountered such a situation (switch lined against me yet having received a Clear signal), I wouldn't just keep a'going.

You're going on the erroneous assumption that all engineers visually inspect the switchpoints of every switch that they operate over to see if the switch is lined in their favor. That's an unrealistic assumption. Not every engineer does that. I would say that any engineer who DOES do that is in the minority. There's just too much else going on up in the cab to focus on and, at some point, an engineer has to prioritize and separate the "important" stuff from the "not so important" stuff. Trying to observe which way hundreds of switch points are lined as you're barreling down on them at high rates of speed is just unrealistic.