Nerd Guru

Because technical people need good soft skills to get ahead.

Thursday, March 06, 2008

A multimillion dollar documentation mistake

The biggest mistake I see young software engineers make is to assume that the product ends once it's cleared testing. If you've been a part of making a great product, it lives on a long, long time beyond the several months you spent building it. Ultimately, the maintenance costs far outweigh the initial development costs and given how frequently people come into and out of teams, documenting how the thing works becomes crucial when later revisions become necessary.

A great example of how not doing this correctly can come back to be quite expensive has reared itself at my beloved Disneyland. A documentation mistake has cost a particular project several million dollars in overage and months in delays. I have a great respect and admiration for Disney's Imagineering department (see Restrictions Breed Creativity) and usually they do a great job morphing attractions over time (see The Old Disneyland Matterhorn), but they've gotten themselves into problems with recent work on the Disneyland Monorail.

Opened on July 14, 1959 the Disneyland Monorail was the first daily operating monorail system in the Western Hemisphere. The winding path it takes through Tomorrowland and over to Downtown Disney is largely the same today as the original line, but the trains themselves have been retrofitted several times over the years of wear and tear. The last of those refurbishments took place during my high school days in the '80s and first of a new fleet of trains arrived at Disneyland this past December.

But, a pretty serious problem surfaced pretty quickly, as reported by longtime Disney fan reporter Al Lutz recently:
"Things began to go wrong just a few days after the new train arrived and was gingerly set down on the beam back at the roundhouse adjacent to Harbor Blvd. The arrival and installation of the train onto the track went fairly smoothly, with the exception of some scuffed up paint caused by the shrink wrap used for shipping.

. . .

When the train was being moved out of the roundhouse and towards the track switch that leads to the mainline at the back of Tomorrowland, the front of the train began to ease through a gentle S-curve that leads from the roundhouse towards the track switch. It was at that point that a grinding and crumpling noise was heard from under the train itself, and the horrified engineer immediately brought the train to a stop."
Crumpling sounds and moving vehicles aren't a good combination. Plus, there are some far tighter turns than the one that gets the train onto the main line, so the problem was way bigger than just this one section.

What happened? With his freaky inside contacts, Al explains:
"There is still a formal investigation yet to be completed, but the smoking gun now appears to be the original 1980's blueprints that were maintained by Disneyland and WDI. Apparently some changes to the chassis were undertaken back in the 1980's prior to entering service, but they never made it onto the blueprints kept on file back in that less technologically savvy time. When one of the old trains was dissected and used in a form of reverse engineering, the difference between the actual chassis and what the blueprints called for helped cause a miscalculation in the dimensions of the new trains chassis. The result is a new train that now has structural damage to the chassis and that still hasn't been able to make it around the track on its own."
I'd argue, though, that the "less technologically savvy time" has little to do with it. The project doesn't end just because your part of it is completed and if you don't properly document what you did, problems can result later. I'm no stranger to making the million dollar mistake myself and this one in particular is an easy one to make, but due diligence when it comes to documentation pays off in the problem you avoid creating later.


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posted by Pete Johnson @ 12:08 PM   0 comments

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