AUSTIN | Transportation Updates

[kingkirbythe....]

Build a trench or tunnel bridge with pedestrian/bike access on top. Problem solved. No dead bats.

[drummer]

Whatever they do, don't put wind turbines on top of the bridge.

[atxsnail]

Originally Posted by kingkirbythe....

Build a trench or tunnel bridge with pedestrian/bike access on top. Problem solved. No dead bats.

Ladybird Lake Bridge Tunnel with attached pedestrian triathlon course


Chesapeake Bay Bridge Tunnel for inspiration:

[freerover]

They should try shifting the bridge further east to hit the end of Rainey St but I don't know how they would get to the lake from the south side if they aren't using the existing easement they have. You would also have to contend with the boardwalk.

[kingkirbythe....]

Thats not what i was saying. I should have been more clear.

The bridge would have walls on both sides. The top would be open like a trench. Walking and biking paths would be cantilevered off the sides at the top of the walls. Or have the walking and biking path be over the top of the train and tracks. This would make the bridge a tunnel.

The like the trench version so the the walking path and the biking path could be more clearly separated. I guess the tunnel version could also have separated walking and biking paths too.

[freerover]

Originally Posted by kingkirbythe....

Thats not what i was saying. I should have been more clear.

The bridge would have walls on both sides. The top would be open like a trench. Walking and biking paths would be cantilevered off the sides at the top of the walls. Or have the walking and biking path be over the top of the train and tracks. This would make the bridge a tunnel.

The like the trench version so the the walking path and the biking path could be more clearly separated. I guess the tunnel version could also have separated walking and biking paths too.

If it's a tunnel then pedestrians will not be allowed in.

[We vs us]

I mean . . . can't you do the bridge with a canopy that goes up and overtop the trains? Bats will echolocate off of the structure and go up and over. Easy peasy.

Here's an example from Chicago:



For bonus points make it out of clear plexiglass!

[kingkirbythe....]

Never said in it.

Walking and biking is on it top of the tunnel the train is in, or walking and biking is cantilevered up and to the side of the trench the train is in.

[ahealy]

I could def see a more narrow Pfluger-style ped bridge with greenery, atop a cylindrical shiney steel "tunnel" bridge. That could actually be really attractive with the right type of soft glowing lighting

[StoOgE]

So, this except with a train and bats.

[electricron]

Originally Posted by eskimo33

I think it was more along the lines of the train running into the bats.

Do buses and cars running on Congress Street Bridge run into bats? Are there dead bats every morning lying in the street? The trains will be in stop and go traffic approaching downtown before entering the tunnels. What speed do you think they will be going approaching the river? If you answered anything over 30 mph, you would be wrong. Check out the speeds of the MetroRail trains under I-35 approaching downtown Austin. You might be surprised how slow it is going. Even light rail trains do not do jack rabbit starts, they gain speed slowly.

I think many posters replying to this thread need to make a trip to either Houston or Dallas and ride some real light rail trains running in the street environment. For Dallas, the Orange Line from either DFW or a short bus ride from Love Field will make a great choice. When in dedicated tracks above streets on a viaduct, or running in dedicated corridor on the surface, it reaches speeds as high as 65 mph. But when operating at grade within streets, max speeds maybe reach 30 mph. You can feel the difference without looking at a speedometer. I'm sure the street environment in Houston will reflect the same speeds.

Guess what the maximum speeds of CapMetro's light rail trains within the street environment speeds will be? I'll bet it will be no faster than the posted speed limits for every other vehicle using the same street.
Light rail routes approaching downtown:
Riverside Drive: 35 mph from South First Street to Vargas Road, 40 mph east of Vargas Road.
South Congress: 30 mph to Riverside, then 35 mph further south.
Guadalupe: 30 mph to 30th, 35 mph to 45th, 40 mph further north.
The light rail trains will not be going 50 or 60 mph as it crosses the river.

If a bat can not avoid a huge train going 30 mph or less on the bridge, it does not deserve to live.

[The ATX]

Originally Posted by electricron

Do cars running on Congress Street run into bats? Are there dead bats every morning lying in the street?

The bats enter and exit their roost under the bridge over the river to the east. They don't fly over the bridge roadway which is why hundreds of people line the bridge on Summer nights without having bats fly into them.

[freerover]

Maybe the bats will move under the blue line bridge instead of congress. That would make for a better place for people to go see the bats assuming there is a pedestrian component.

[Enghum]

The only mitigation I could imagine is maybe limiting train speed in the evening if the trains do happen to start mowing over bats. There are also stations located on either side of the lake so this isn't going to be a high speed section of the blue line.

Mexican free-tailed bats are extremely adept at flying. They are also extremely adept at not running into things. These bats are evolved to fly out with millions of their companions in tight spaces and not run into each other. In fact the Mexican free-tailed bats are known to be the highest flying bats. They are also very fast when they want to be. If there was a race between the bat and our train the bat would win.

The distance of the proposed bridge is over 1300 feet away. Over twice the distance of 1st street bridge which has no bat conflict that I've heard of. I know the bats prefer to exit towards the east to the area we are talking about but they need to get up 30 ft in elevation across a 1300 foot distance. That's relatively easy for a bat species known to travel 50 miles a night to feed.

[hereinaustin]

Better yet, just tunnel under the river and keep the space above open.

[ahealy]

I just wish this city has a gorgeous arched bridge that was attractive and stunning. We need something that pops when you're driving in from S35.

....OR an "underwater" tunnel

[electricron]

Originally Posted by hereinaustin

Better yet, just tunnel under the river and keep the space above open.

Congress and Riverside per elevation charts is around 425 feet above sea level. The Colorado River is around 400 feet above sea level. The base of a rail tunnel under the Colorado River would have to be at least 25 feet lower than the river, accounting for track bed, tracks, and catenary wires above the trains. That's assuming a square shaper tunnel, an arch shaper tunnel might need to be deeper. So the tunnel will have to have at least a 50 feet vertical drop (or rise) from a southern portal near Riverside. The northern portal is in this case unimportant because the trains will be running supposedly in a subway north of the river. Google Earth tools suggests Riverside is 950 feet away from the rivers southern bank opposite Trinity north of the river (just about everyone's choice for the rail line route.
Some math follows
Best case scenario using every foot for the grade placing the portal at Riverside's northern curb
50/950 x 100 = 5.25% grade.
That is very steep, even for light rail trains. But doable because almost all light rail trains are allowed 6% grades. It is not the propulsion machinery capability to climb uphill that limits the grades, it is the braking capability of the brakes on the downhill that is more limiting. There are just so many brakes you can put on an axle.
If they were to build a bridge over the river at the same location, then where the northern portal is place would be more important. But CapMetro would have the advantage of reducing the vertical elevation change to 25 feet or so, since they wouldn't have to go lower than the river anymore. It should be easy for them to do that. So not only should the bridge over the river be cheaper to build, it should be easier to operate trains on as well.

A great example where construction photos are still present of light rail going underground to a station at Google Earth is the Rideau Station just east of the Rideau Canal in Ottawa to the southeast portal to its' south. 2000 feet to drop around 87 feet.
Per https://en.wikipedia.org/wiki/Rideau_station
It is 26.5 meters deep or 87 feet deep.
2000 feet in a direct line between portal and eastern edge of station construction visible using Google Earth tools.
Math = 87/2000 x 100 = 3.95% grade. Far less than the 6% grade discussed earlier.

[ahealy]

So.... let me ask a dumbass question here. What is up with our toll roads? Will 130 & 45 always be a tolls? I am in RR/CP a lot these days and find it absolutely ridiculous how confusing life is if you choose to not use the tolls. Is the plan that it'll be like 1604 in SA?

Currently, it's a nightmare and I hate it.

[chinchaaa]

Originally Posted by ahealy

So.... let me ask a dumbass question here. What is up with our toll roads? Will 130 & 45 always be a tolls? I am in RR/CP a lot these days and find it absolutely ridiculous how confusing life is if you choose to not use the tolls. Is the plan that it'll be like 1604 in SA?

Currently, it's a nightmare and I hate it.

I agree. People should be more outraged about all the toll roads.

[Novacek]

Originally Posted by ahealy

So.... let me ask a dumbass question here. What is up with our toll roads? Will 130 & 45 always be a tolls? I am in RR/CP a lot these days and find it absolutely ridiculous how confusing life is if you choose to not use the tolls. Is the plan that it'll be like 1604 in SA?

Currently, it's a nightmare and I hate it.

Under our current system, toll roads aren't going away and tolls will never be removed from existing toll roads. There's no concept of a road eventually being "paid off", because:

1. Even if you got to that point, you still need money for upkeep, maintenance, renewal, and potentially expansion of that road.

2. The tolls don't go to just that one road, but to the entire system. Part of the tolls on the existing roads go to expanding the system and adding new roads.

That's the current system, driven in part by the gas tax never being indexed to inflation and not increasing in 3 decades (and counting). Increased fuel efficiency and moving to electric vehicles (though generally a good thing) further decrease revenue. It's unlikely Texans would accept a more invasive replacement funding system of tracking their VMT at registration. Plus the downside to that approach would be failures to get revenues for travelers and interstate shipping that take advantage of Texas roads.

Tolls are here to stay, unless TxDot and CTRMA get out of the business of building new highways. And even then, you still have (1) unless they start actively tearing them down.

Originally Posted by chinchaaa

I agree. People should be more outraged about all the toll roads.

I agree, I'm outraged there aren't more tolls. I'm outraged that CAMPO money that was supposed to go to local projects is now instead going to non-toll lanes on I35 that (in part) benefit non-residents.