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Re: Rename the Tom Lantos Tunnels!
Author: observer
Date: 02-13-2019 - 13:01
Del Mar v. @#$%& Slide
* @#$%& Slide shorter. Length has a direct impact on cost.
* @#$%& Slide in rural/parkland area; Del Mar in built-up area. Localized impacts are more widespread and costly to mitigate in Del Mar.
* No shallow/cut&cover sections on @#$%& Slide - almost all hard rock. Del Mar will need some cut/cover and/or trench construction in shallow spots, even for the alternatives that are mostly bored. Cost is probably a wash except for urban mitigation measures needed at Del Mar.
* Rock in Del Mar likely softer (possibly allowing use of a boring machine) than the granite and shearzones full of water at @#$%& Slide. Ease of construction goes to Del Mar.
* 10 years later for Del Mar, closer to 25-30 years by the time construction happens; construction cost inflation way higher than retail prices. This is probably the biggest contributor to the higher cost at Del Mar.
* All-Caltrans at @#$%& Slide; SANDAG at Del Mar. Both are interested in minimizing cost.
* For cars and trucks at @#$%& Slide (known quantities re. emissions, smaller bore); railroad at Del Mar (with clearance for doublestacks & eventual electrification). All things being equal, possibly bigger bores at Del Mar (double track...) and more interesting ventilation needs (diesel locomotives at least initially). Plus escape/evac requirements that don't usually exist for car tunnels. Size and number of holes has a direct effect on the cost.
All things considered, it's not surprising at all that a double track railroad tunnel under Del Mar would cost more than a highway tunnel 10+ years ago (20-30 years by the time construction happens) did at @#$%& Slide.
* @#$%& Slide shorter. Length has a direct impact on cost.
* @#$%& Slide in rural/parkland area; Del Mar in built-up area. Localized impacts are more widespread and costly to mitigate in Del Mar.
* No shallow/cut&cover sections on @#$%& Slide - almost all hard rock. Del Mar will need some cut/cover and/or trench construction in shallow spots, even for the alternatives that are mostly bored. Cost is probably a wash except for urban mitigation measures needed at Del Mar.
* Rock in Del Mar likely softer (possibly allowing use of a boring machine) than the granite and shearzones full of water at @#$%& Slide. Ease of construction goes to Del Mar.
* 10 years later for Del Mar, closer to 25-30 years by the time construction happens; construction cost inflation way higher than retail prices. This is probably the biggest contributor to the higher cost at Del Mar.
* All-Caltrans at @#$%& Slide; SANDAG at Del Mar. Both are interested in minimizing cost.
* For cars and trucks at @#$%& Slide (known quantities re. emissions, smaller bore); railroad at Del Mar (with clearance for doublestacks & eventual electrification). All things being equal, possibly bigger bores at Del Mar (double track...) and more interesting ventilation needs (diesel locomotives at least initially). Plus escape/evac requirements that don't usually exist for car tunnels. Size and number of holes has a direct effect on the cost.
All things considered, it's not surprising at all that a double track railroad tunnel under Del Mar would cost more than a highway tunnel 10+ years ago (20-30 years by the time construction happens) did at @#$%& Slide.
