The difficulties of projecting costs for big tunnel projects

Cost overruns on big infrastructure projects are common but may be even worse for tunnel projects, as the case of the California high-speed rail project may soon illustrate:

“You have an 80% to 90% probability of a cost overrun on a project like this,” Flyvbjerg said. “Once cost increases start, they are likely to continue.”…

Although some large tunnels have been constructed elsewhere without difficulty, including the 3,399-foot Caldecott Tunnel in the Bay Area, others have encountered costly problems.

The 11-mile East Side Access tunnel in New York City, for example, is 14 years behind schedule, and the tab has grown from $4.3 billion to $10.8 billion. Boston’s 3.5-mile Big Dig was finished in 2007 — nine years behind schedule and at nearly triple the estimated cost.

Digging stopped on the 2-mile Alaskan Way tunnel under Seattle when a boring machine broke down in December 2013 and had to be retrieved for repairs, causing a multiyear delay with an unknown cost overrun.

The bullet train will require about 20 miles of tunnels under the San Gabriel Mountains between Burbank and Palmdale, involving either a single tunnel of 13.8 miles or a series of shorter tunnels.

As many as 16 additional miles of tunnels would stretch under the Tehachapi Mountains from Palmdale to Bakersfield.

All told, this is a major project that might just draw attention from the public and scholars for decades to come. Is it possible to even finish it? What will be the end cost? Will it enhance transportation and life in California? There is a lot at stake here and big costs will not help. From the article, it sounds like part of this is due to falling behind schedule – this adds more money as the project takes more time and costs tend to go up over time – and is also due to the unique geological features of California – fault lines and possible earthquakes – which produce additional complications.

I’ve seen numerous people suggest that projects like these illustrate how difficult it is for the United States of today to complete major projects. This may be needed and/or helpful but a lot of good things have to happen before the line even becomes operational.

Explaining the tunnel system under Liverpool

Excavations have brought to light tunnels under Liverpool but it is unclear why a tobacco merchant created them in the early 1800s:

He also had men build tunnels. One entrance to the system even has been found in the basement of his former house. But why tunnels? Did he ask them to build his tunnels arbitrarily, for no other purpose than to be paid for work? It seems extraordinary. And yet there are no known records from Williamson’s time which offer anything like an explanation for their construction.

Instead, succeeding generations and historians have had to guess – leading to all manner of speculation. Perhaps Williamson wanted secret passages to get to and from buildings in Edge Hill. Or was a smuggler and needed the tunnels to carry out covert operations.

Or maybe he and his wife belonged to a fanatical religious cult that anticipated the end of the world, and his tunnels were designed to provide shelter during the apocalypse. Apparently, someone once made the suggestion casually on television, and the idea since stuck.

Those who have worked on the tunnels have now developed a new, somewhat more satisfying theory. Bridson points out a series of markings in the sandstone that he says are indicative of quarrying. There are channels to drain rainwater away from the rock while men worked, blocks out of which sandstone could be hewn, and various niches in the walls where rigs were once likely installed to help with extracting the stone, commonly used as a building material.

Bridson believes that before Williamson came along, these pits in the ground already existed. But it was Williamson’s idea to construct arches over them and seal them in. Properties could then be built on top of the reclaimed land – which otherwise would have been practically worthless.

I imagine there are interesting things lurking under every major city as evidenced by findings under Paris, Chicago, Seattle, London, and New York.

The land development theory is an interesting one. Williamson could benefit in two ways: by selling the excavated rock from below the surface and then also selling the land above it. Now, there might be separate rights to the above ground and below ground space but no such issues likely hindered Williamson.

Exploring the “mail rail” of London

There seems to be a growing interest in stories about underground spaces below cities. Add another to stories about underground Paris, New York, and Las Vegas: several explorers have documented the “mail rail” system that operated not too long ago beneath London:

Construction of the tunnels began on February 1915 from a series of shaft located along the route. The tunnels were primarily dug in clay using the Greathead shield system, although the connecting tunnels in and around the stations were mined by hand…

It wasn’t until June 1924 that workers began laying the track using 1000 tons of running rail and 160 tons of conductor rail…The line was eventually finished in 1927 with the first letter through the system running on February 1928…

Although initially the system was a success, in its last years of service the line was continually losing money. On the 7th November 2002, Royal Mail announced the line had become uneconomical with losses of £1.2M a day and that they planned to close it should no alternate uses be found. This was to be the death of the Mail Rail with the line from Mount Pleasant to the Eastern Delivery Office closing on the 21st March 2003, the remaining section from the Western District Office to Mount Pleasant following on the 29th. Now it just sits there buried where light cannot reach, rusting away, the trains sleeping silently in and around the stations wanting to be used again. Sadly a dream which we all know will never come true.

I had not known that these sorts of mail systems were in use until so recently. Such systems were not completely unknown in big cities: Chicago had a much more complex system that delivered mail as well as other kinds of freight. In big yet dense cities, these delivery systems could make a lot of sense as it would keep some traffic off the roads and goods could be delivered with little interruption.

I do wonder at times whether current city officials are very knowledgeable about what is underneath their cities. The pictures regarding London’s “mail rail” are quite good and I wonder if they caught anyone off-guard.

With such interesting things underneath so many big cities, it seems that movie and TV writers would have an endless supply of interesting settings where odd things could occur and creatures could roam…

Quick Review: Georgia Aquarium

While recently in Atlanta, I had a chance to make a brief visit to the Georgia Aquarium. Some quick thoughts:

1. Overall, a beautiful facility. Well-designed with an interesting central space/lobby. Vivid exhibits. The only downside was the large crowds in some of the exhibits.

2. The best part were the large tanks. This aquarium doesn’t have a lot of individual tanks featuring a lot of different species. The emphasis is on large tanks, particularly in the Ocean Voyager exhibit. While this exhibit features some rare animals such as the whale shark (unbelievably large), this has numerous great viewing points plus a tunnel underneath the middle of the tank. The viewing theater space at the end of the exhibit was a location where I could sit for a long time just watching the animals swim by. Here is an image of the whale shark from the viewing theater:

3. There were a number of innovative ways to view the tanks. In addition to the tunnel in the Ocean Voyager exhibit, I walked through a small tunnel with glass ceilings (probably three feet tall) under a river exhibit. The penguin exhibit featured special “bubbles”: people would walk up into the exhibit from below and while surrounded by a plastic bubble perhaps four feet across, see eye-to-eye with the penguins.

4. There is a special shark exhibit that didn’t feature any live sharks but had a lot of information on fossil teeth, different shark species, and interactions with humans. One room featured a frozen giant tuna next to a large shark and talked about how sharks chased tunas in the ocean depths. On one hand, the exhibit said sharks were dangerous creatures (with a particular emphasis on their teeth and jaws). On the other hand, the exhibit kept saying that the media and Hollywood have over-hyped shark attacks.

5. The aquarium seemed pretty kid-friendly, particularly in the Georgia Coast exhibit where patrons could touch a number of animals (I touched a small shark, stingrays, along with a few other small and more fixed creatures) and kids could crawl around in some cool-looking equipment.

6. Like many museums today, it was pricey: around $31 for what I saw (and I didn’t purchase all the add-ons).

Even with the price and the crowds, this was well worth the money. I thought the Shedd Aquarium was a lot of fun – this relatively new aquarium is vastly superior.