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Signs in East Boston, Chelsea and Revere to flash alerts when the Chelsea Street Bridge is up
By adamg on Wed, 06/14/2017 - 3:23pm
MassDOT reports it's turning on a network of eight signs on roads leading to the Chelsea Street Bridge that will alert motorists when the bridge is unpassable because a boat is passing underneath or it's otherwise stuck and unable to carry traffic.
The total cost for developing and installing the new notification system for the Chelsea Street Bridge was approximately $234,000. The bridge handles a daily volume of approximately 37,000 vehicles and is raised an average of 5 times per day to allow for the passage of incoming vessels.
The Chelsea Street Bridge was constructed in 2012 and carries traffic on Chelsea Street over the Chelsea Creek. The bridge is approximately 450 feet in length and when raised has a vertical clearance of approximately 175 feet.
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Comments
Chelsea St. Bridge
I've had to wait in that ungodly line before. Does the bridge get raised to its maximum height for every craft which passes through, regardless of the boat's height? Could the bridge be raised only as high as necessary for the approaching craft?
Not sure about this bridge in
Not sure about this bridge in particular, but with vertical lift bridges usually yes, they are raised their full height every time. This is both to simplify the machinery, and reduce the potential for human error (e.g. what if the crew of a ship calls to request a bridge opening, but misstates their height? Or if the operator selects the wrong height accidentally?).
It's easier to just have it go all the way up. Raising and lowering it doesn't take more than a few minutes anyway, so it's not that big of a deal.
More than a few
I think the last time I paid attention it took around 15-20 minutes. Also traffic backs up a fair distance so it can be several light cycles after the bridge is down before you get through.
The time
The time is caused by the boat itself. Sometimes they get warning to go up but it could be a few minutes until the boat is at the bridge.
The bridge itself can take 3-5 minutes to raise and 3-5 minutes to lower.
So even if the boat zipped
So even if the boat zipped through in 10 seconds, the bridge itself causes a 10 minute delay.
According to the Time stamps
According to the Time stamps on the Twitter account Cybah posted we are looking at between 15 minutes to 32 minutes (quick math) with most taking 25ish minutes from close to open.
I knew it took for ever but DAMN I did not realize that consistently we were talking almost a half hour every time. Just for the bridge. Never mind how long it takes for traffic to normalize after the fact.
It should be up the captain's
It should be up the captain's discretion to pass under a partially-raised bridge. The same way the captain decides if the ship can fit under a fixed bridge at the current tide level. They could paint markings on the bridge that show how high it's been raised, so no they don't have to depend on (mis)communication with the bridge operator.
This video shows that it takes at least 4 and a half minutes just to go up: https://www.youtube.com/watch?v=bGrTl6WF6to People say it can be up for half an hour.
This 12-minute video shows 7 minutes for the ships to pass, plus 5 minutes to lower. I'm glad they're playing WJIB -- it's a good way to keep calm when you're stuck for that long. https://www.youtube.com/watch?v=mW-oztsOBQo
The increased vertical clearance and channel depth means bigger, slower ships can pass through.
This will be particularly fun for on-time performance on the new Chelsea branch of the Silver Line.
Here's the old bridge for comparison, right before it was closed in 2011. It was a bascule bridge, which meant it just had to rotate out of the way, rather than lifting up higher than the tallest possible ship. https://www.youtube.com/watch?v=29rl7LoKqNI
Water Storrow?
Um. No thanks.
Exactly. Even though the
Exactly. Even though the skill level is much higher to be the captain of a ship than to drive a car, people have clearly demonstrated that they are incapable of comprehending a clearance sign for an overpass, so I don't expect any different for a ship going under a bridge.
Also, as I said above, it would save minimal time. Even if it takes 5 minutes to raise/lower the bridge, and 7 minutes for the ship to pass, raising it only 2/3 of the way is probably only going to save you 2 minutes of delay - the height the bridge is raised is not evenly distributed over that 5 minute time. So your 2 minutes of delay comes at the cost of increased risk for a ship to strike the bridge, and increased construction and maintenance and inspection costs for the more complicated machinery. No thank you.
Finally, the old bridge was not a bascule span. It was a swing span. Bascules lift each side at an angle (e.g. the bridge on Morrissey Blvd, and the Alford St bridge). And swing spans may not have any limit on vertical clearance, but they do tend to require a narrow channel, aren't any faster at opening/closing, and are more expensive to maintain.
Nope. The old Chelsea Street bridge
was a bascule bridge, not a swing span.
https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=15...
So it was! Thanks for the
So it was! Thanks for the correction. I wasn't around when that was replaced, so I was going based off of the youtube video, which is terrible quality, and the fact that he said:
which is describing a swing span instead of a bascule span.
Bascules do rotate, just not
Bascules do rotate, just not horizontally.
Well yes, but again, let me
Well yes, but again, let me provide the quote I was responding to:
That sure sounds to me like describing a swing span, not a bascule.
Saving 2 minutes is huge. 1/3
Saving 2 minutes is huge. 1/3 of the 10 minute cycle time is about 3 minutes. And it could save more than that if the bridge raises less than 2/3.
As I said above, captains
As I said above, captains *already do* make an overhead clearance judgement call, *every* time they pass below a fixed bridge.
Yes, but as I said above,
Yes, but as I said above, there's an extra human involved in this - the bridge operator. And there's plenty of potential for miscommunication between them. The captain could get the height wrong. The bridge operator could mishear the height. The bridge operator could select the wrong height. All of those risks are eliminated by just raising the bridge all the way.
Going under a fixed bridge only requires one person to make the judgement call, rather than relying on communication between two people. There are a lot fewer failure points.
I don't really understand why we're having this argument though - I feel like the fact that the bridge does raise all the way every time clearly indicates that yes, there is a reason that is the case. If it was practical to only partially raise it, they'd be doing that. But everyone on the internet always seems to think they know better than the professionals who do these things for a living.
Reminds me of an old saying -
Reminds me of an old saying - something like:
There are three things the any man thinks he can do better than any other man - build a fire, run a hotel, and manage a ball team.
I know hardly anything about the guts of drawbridges, but I wonder if it would be more expensive and/or impractical to build one that routinely used different stopping heights. It seems like there would be some sort of parking brake or safety lock or something at the stopping position (either on the towers or changing the wear & tear on the cable & winch), right? Otherwise, someone could accidentally hit the "down" button when a ship was in the wrong spot. If they built in stopping positions every 10 feet or so between 95 feet raised and 175 feet raised, that's 7 extra setups. It would cost a little more to build and there would be more points to maintain.
What about the Meridian Street bridge?
Shouldn't it get the signs, also?
Timer?
Also, could they add a timer, so we know about how long we will sit in traffic for?? OR if we should try to race to the other bridge.
Thanks!
Save yourself the trouble,
Save yourself the trouble, and go up to Route 16. Except of course if you're walking, biking, or taking a bus, in which case you have no choice but to wait.
It'd be too difficult to
It'd be too difficult to accurately predict. The boat might be a few minutes late. There might be an issue getting the bridge to lock into place.
People are placated by providing a countdown only if that countdown is highly accurate. Otherwise it tends to make people more frustrated.
You're welcome?
I suggested this very thing for a different drawbridge — 10 years ago:
http://archive.boston.com/news/local/articles/2007/12/09/no_signs_relate...
SL3
Part of this is because of the Silver Line Gateway. Its apart of the plan to notify passengers so they can take another route. The same system is being used here for the signage.
There's actually a Twitter handle for the bridge that does announce when it's up and down. Not sure if its automatic or someone in the bridge does it (I only say this because the text can vary from tweet to tweet depending the time of day.
I agree with Ron. I wish the Meridian Street bridge had this to. It would be helpful too.
Omfg you're doing gods work
Omfg you're doing gods work cybah!!!! I've been looking for an alert system like the Twitter handle for awhile!!! It really make a huge difference in my commute!!!!
Link?
Is there a link for this report somewhere?
They e-mailed me a press release
I can post the whole thing if you like.
http://blog.mass.gov
http://blog.mass.gov/transportation/massdot-highway/new-chelsea-street-b...