What type of rock did the engineers encounter when constructing the Bergen Hill Tunnels?
- Sandstone
- Limestone
- Diabase
- Granite
Correct Answer: Diabase
Correct Answer Explanation: The Bergen Hill Tunnels passed through a trap dike, which is a geological formation where igneous rock has intruded into sedimentary rock. Diabase, also known as trap rock, is a type of igneous rock commonly found in trap dikes.
What innovative drilling technique was used to speed up excavation in the Bergen Hill Tunnels?
- Using explosives
- Using a single drill per heading
- Using multiple drills per heading
- Using hand tools
Correct Answer: Using multiple drills per heading
Correct Answer Explanation: To increase excavation speed, the engineers employed multiple-drill headings, with as many as eight drills working simultaneously. This technique allowed them to drill multiple holes at the same time, significantly reducing the overall drilling time.
What was a major challenge encountered during the construction of the Bergen Hill Tunnels?
- The tunnels were too short
- The tunnels were too long
- There was a lack of materials
- Ventilation was poor
Correct Answer: Ventilation was poor
Correct Answer Explanation: Smoke from blasting and locomotives created a significant ventilation challenge, especially in the Hackensack tunnel with its ascending grade. The engineers employed a series of fans and blowers to improve air circulation and mitigate the smoke and fog issues.
Which of these methods was NOT used to construct the Bergen Hill Tunnels?
- Cut-and-cover method
- Center top heading method
- Drill and blast method
- Shaft sinking method
Correct Answer: Cut-and-cover method
Correct Answer Explanation: The Bergen Hill Tunnels were constructed using the center top heading method and the drill and blast method. The cut-and-cover method, where an open trench is excavated and then covered with a roof, is typically used in shallower tunnels or for underground structures where excavation is done from the surface.
What did engineers use to move concrete buckets to the platform above?
- Cranes
- Conveyor belts
- Hoists
- Traveling gantries
Correct Answer: Traveling gantries
Correct Answer Explanation: Traveling gantries were used to hoist concrete buckets from rail cars to the platform above, allowing for efficient placement of concrete in the arch and bench walls.
What geological feature presented a challenge to the construction of the Bergen Hill Tunnels?
- A fault zone
- A sinkhole
- A landslide
- A cave
Correct Answer: A fault zone
Correct Answer Explanation: The tunnels pass through a fault zone for nearly 400 feet, presenting challenges due to unstable ground and requiring extensive timbering.
How was water-proofing achieved in the Bergen Hill Tunnels?
- Using a layer of concrete
- Using a layer of asphalt
- Using layers of felt and pitch
- Using a layer of clay
Correct Answer: Using layers of felt and pitch
Correct Answer Explanation: To prevent water infiltration, the tunnels were water-proofed using six-ply felt and seven layers of pitch, especially in the wet sections near the river.
What was the average time required to drill a 10-foot hole in the hardest trap rock encountered in the tunnels?
- 2 hours
- 5 hours
- 10 hours
- 20 hours
Correct Answer: 10 hours
Correct Answer Explanation: The hardest trap rock encountered in the tunnels had a specific gravity of 2.98, making it extremely difficult to drill. The average time to drill a 10-foot hole in this rock was almost 10 hours.
What was the primary method of excavation used for the Bergen Hill Tunnels?
- Cut-and-cover method
- Shield method
- Drill and blast method
- Trench method
Correct Answer: Drill and blast method
Correct Answer Explanation: The Bergen Hill Tunnels were excavated using the drill and blast method, which involves drilling holes into the rock and then using explosives to break it up.
What was the average progress per working day in each of the Bergen Hill Tunnels?
- 2 feet
- 4 feet
- 6 feet
- 8 feet
Correct Answer: 6 feet
Correct Answer Explanation: The average progress per working day in each tunnel was 6.26 feet.
How many days were worked on the Bergen Hill Tunnels in total?
- 200 days
- 500 days
- 940 days
- 1,500 days
Correct Answer: 940 days
Correct Answer Explanation: The total number of days worked on the tunnels was 940 days.
What was the primary cause of lost time during the construction of the Bergen Hill Tunnels?
- Lack of funding
- Labor strikes
- Equipment failures
- Delays by the Receiver of the Shields Company
Correct Answer: Delays by the Receiver of the Shields Company
Correct Answer Explanation: 40 days of work were lost due to delays by the Receiver of the Shields Company, a significant setback in the overall project schedule.
What was the average quantity of dynamite used for advancing the main working faces in the Bergen Hill Tunnels?
- 1 pound
- 2.5 pounds
- 5 pounds
- 10 pounds
Correct Answer: 2.5 pounds
Correct Answer Explanation: The average quantity of dynamite used for advancing the main working faces was 2.5 pounds.
What was the depth of the shaft sunk at Central Avenue?
- 100 feet
- 150 feet
- 212 feet
- 300 feet
Correct Answer: 212 feet
Correct Answer Explanation: A shaft 212 feet deep was sunk at Central Avenue, located 3,620 feet from the Weehawken Shaft.
What was the main purpose of the Bergen Hill Tunnels?
- To transport water
- To transport sewage
- To transport freight and passengers
- To transport oil
Correct Answer: To transport freight and passengers
Correct Answer Explanation: The Bergen Hill Tunnels were a crucial part of the Pennsylvania Railroad’s New York Tunnel Extension, designed to transport freight and passengers between New Jersey and New York City.
What was the average quantity of powder used per cubic yard for the entire Bergen Hill Tunnel project?
- 1 pound
- 2 pounds
- 2.9 pounds
- 4 pounds
Correct Answer: 2.9 pounds
Correct Answer Explanation: The average quantity of powder used on the entire work was about 2.9 pounds per cubic yard.
What was the average rate of progress for each working face per day in the Bergen Hill Tunnels?
- 1 foot
- 2 feet
- 3 feet
- 4 feet
Correct Answer: 3 feet
Correct Answer Explanation: The average rate of progress for each working face per day was 3.13 feet.
What was the maximum output of a steam shovel in one shift?
- 50 cubic yards
- 100 cubic yards
- 159 cubic yards
- 200 cubic yards
Correct Answer: 159 cubic yards
Correct Answer Explanation: The maximum output of a steam shovel in one shift was 159 cubic yards.
What was the average depth drilled per hour while the drills were “actually working” in the Bergen Hill Tunnels?
- 1 foot
- 1.5 feet
- 2.66 feet
- 4 feet
Correct Answer: 2.66 feet
Correct Answer Explanation: The average depth drilled per hour, during the time the drills were “actually working”, was 2.66 feet.
What was the average length of heading driven per day worked in the North West section of the Central Shaft?
- 2 feet
- 3 feet
- 4.4 feet
- 6 feet
Correct Answer: 4.4 feet
Correct Answer Explanation: The average length of heading driven per day worked in the North West section of the Central Shaft was 4.4 feet.
What was the average time required to drill one foot of normal trap rock in the Bergen Hill Tunnels?
- 10 minutes
- 15 minutes
- 20 to 25 minutes
- 30 minutes
Correct Answer: 20 to 25 minutes
Correct Answer Explanation: The average time to drill one foot of normal trap rock was 20 to 25 minutes.
What was the average quantity of water flowing out of the tunnel drains after the completion of the lining?
- 25 gallons per minute
- 50 gallons per minute
- 75 gallons per minute
- 100 gallons per minute
Correct Answer: 75 gallons per minute
Correct Answer Explanation: The quantity of water flowing out of the tunnel drains after the completion of the lining was 75 gallons per minute.
What was the average length of heading driven per day worked in the North East section of the Central Shaft?
- 2 feet
- 3.5 feet
- 4.5 feet
- 6 feet
Correct Answer: 4.5 feet
Correct Answer Explanation: The average length of heading driven per day worked in the North East section of the Central Shaft was 4.5 feet.
What was the average rate of progress per day in the ordinary trap rock section at Weehawken?
- 2 feet
- 3 feet
- 4.55 feet
- 6 feet
Correct Answer: 4.55 feet
Correct Answer Explanation: The average rate of progress per day in the ordinary trap rock section at Weehawken was 4.55 feet.
What was the average rate of progress per day in the timbered section at Weehawken?
- 1 foot
- 1.5 feet
- 2.3 feet
- 3 feet
Correct Answer: 2.3 feet
Correct Answer Explanation: The average rate of progress per day in the timbered section at Weehawken was 2.3 feet.
What was the average rate of progress per day in the hard trap rock section at Weehawken?
- 1.5 feet
- 2 feet
- 2.4 feet
- 3 feet
Correct Answer: 2.4 feet
Correct Answer Explanation: The average rate of progress per day in the hard trap rock section at Weehawken was 2.4 feet.
What was the average rate of progress per day in the hard sandstone section at Weehawken?
- 2.5 feet
- 3 feet
- 3.2 feet
- 4 feet
Correct Answer: 3.2 feet
Correct Answer Explanation: The average rate of progress per day in the hard sandstone section at Weehawken was 3.2 feet.
What was the total “actual working time” of drills over 736 shifts?
- 1,000 hours
- 2,000 hours
- 3,826 hours
- 5,000 hours
Correct Answer: 3,826 hours
Correct Answer Explanation: The total “actual working time” of drills over 736 shifts was 3,826 hours.
What was the best week’s work at a working face, equivalent to 803 cubic yards?
- 20 linear feet
- 30 linear feet
- 41.8 linear feet
- 50 linear feet
Correct Answer: 41.8 linear feet
Correct Answer Explanation: The best week’s work at a working face was 41.8 linear feet, equivalent to 803 cubic yards.
What was the largest number of yards taken out in any one week from one working face, equivalent to 1,087 cubic yards?
- 40 linear feet
- 50 linear feet
- 56.6 linear feet
- 60 linear feet
Correct Answer: 56.6 linear feet
Correct Answer Explanation: The largest number of yards taken out in any one week from one working face was 56.6 linear feet, equivalent to 1,087 cubic yards.
What was the total linear feet of full-section tunnel equivalent to 3,238 cubic yards taken out in one week from four working faces?
- 100 linear feet
- 150 linear feet
- 168.4 linear feet
- 200 linear feet
Correct Answer: 168.4 linear feet
Correct Answer Explanation: The total linear feet of full-section tunnel equivalent to 3,238 cubic yards taken out in one week from four working faces was 168.4 linear feet.
What was the average time per foot drilled in the bench?
- 20 minutes
- 30 minutes
- 36.6 minutes
- 45 minutes
Correct Answer: 36.6 minutes
Correct Answer Explanation: The average time per foot drilled in the bench was 36.6 minutes.
What was the average depth drilled per hour in the bench?
- 1 foot
- 1.5 feet
- 1.64 feet
- 2 feet
Correct Answer: 1.64 feet
Correct Answer Explanation: The average depth drilled per hour in the bench was 1.64 feet.
What was the best average monthly output of a steam shovel?
- 20 cubic yards
- 40 cubic yards
- 60 cubic yards
- 80 cubic yards
Correct Answer: 60 cubic yards
Correct Answer Explanation: The best average monthly output of a steam shovel was 60 cubic yards.
What was the average quantity actually handled by a steam shovel per shift?
- 50 cubic yards
- 70 cubic yards
- 90 cubic yards
- 100 cubic yards
Correct Answer: 90 cubic yards
Correct Answer Explanation: The average quantity actually handled by a steam shovel per shift was 90 cubic yards.
What was the average actual advance per day worked in the bench and enlargement of the Central Shaft headings?
- 5 feet
- 6 feet
- 7.2 feet
- 8 feet
Correct Answer: 7.2 feet
Correct Answer Explanation: The average actual advance per day worked in the bench and enlargement of the Central Shaft headings was 7.2 feet.
What was the distance from the Weehawken Shaft where hand mucking was used?
- 500 feet
- 750 feet
- 1,000 feet
- 1,250 feet
Correct Answer: 1,000 feet
Correct Answer Explanation: Hand mucking was used for a distance of 1,000 feet from the Weehawken Shaft.
How much more excavation was taken out than what the contractor was required to excavate?
- 10%
- 15%
- 28%
- 40%
Correct Answer: 28%
Correct Answer Explanation: The excavation was taken out 28% more than what the contractor was required to excavate.
How much more excavation was taken out than what was paid for?
- 10%
- 15%
- 20%
- 25%
Correct Answer: 10%
Correct Answer Explanation: The excavation was taken out 10% more than what was paid for.
What was the specific gravity of the hardest trap rock found in the Bergen Hill Tunnels?
- 2.6
- 2.8
- 2.98
- 3.2
Correct Answer: 2.98
Correct Answer Explanation: The specific gravity of the hardest trap rock found was 2.98.
What was the average time the drills were “actually working” per shift in the Bergen Hill Tunnels?
- 4 hours
- 5.2 hours
- 6 hours
- 7 hours
Correct Answer: 5.2 hours
Correct Answer Explanation: The average time the drills were “actually working” was 5.2 hours per shift.
What was the depth that was sunk in the Central Shaft in 6 months?
- 150 feet
- 175 feet
- 205 feet
- 250 feet
Correct Answer: 205 feet
Correct Answer Explanation: A depth of 205 feet was sunk in the Central Shaft in 6 months.
What was the specific gravity of the normal trap rock found in the Bergen Hill Tunnels?
- 2.5 to 2.7
- 2.85 to 3.04
- 3.0 to 3.2
- 3.2 to 3.4
Correct Answer: 2.85 to 3.04
Correct Answer Explanation: The normal trap rock in the tunnels had a specific gravity ranging from 2.85 to 3.04.
What was the weight per cubic foot of the hardest trap rock found in the Bergen Hill Tunnels?
- 150 pounds
- 175 pounds
- 186 pounds
- 200 pounds
Correct Answer: 186 pounds
Correct Answer Explanation: The hardest trap rock found in the tunnels weighed 186 pounds per cubic foot.
What was the weight per cubic foot of the normal trap rock found in the Bergen Hill Tunnels?
- 150 to 170 pounds
- 160 to 180 pounds
- 179 to 190 pounds
- 180 to 200 pounds
Correct Answer: 179 to 190 pounds
Correct Answer Explanation: The normal trap rock in the tunnels weighed from 179 to 190 pounds per cubic foot.
What was the distance between the Weehawken Shaft and Central Avenue?
- 2,500 feet
- 3,000 feet
- 3,620 feet
- 4,000 feet
Correct Answer: 3,620 feet
Correct Answer Explanation: The distance between the Weehawken Shaft and Central Avenue was 3,620 feet.
What was the length of each tunnel between the portals?
- 4,000 feet
- 5,000 feet
- 5,920 feet
- 6,000 feet
Correct Answer: 5,920 feet
Correct Answer Explanation: The length of each tunnel between the portals was 5,920 feet.
What was the grade of the Bergen Hill Tunnels?
- 0.5%
- 1.0%
- 1.3%
- 1.5%
Correct Answer: 1.3%
Correct Answer Explanation: The tunnels have a grade of 1.3% ascending from east to west.
Where are the Bergen Hill Tunnels located?
- East of the Hudson River
- West of the Hudson River
- North of the Hudson River
- South of the Hudson River
Correct Answer: West of the Hudson River
Correct Answer Explanation: The Bergen Hill Tunnels are located west of the Hudson River and pass through a trap dike known as Bergen Hill.
What was the temperature in the Bergen Hill Tunnels?
- 40 to 50 degrees
- 50 to 60 degrees
- 60 to 70 degrees
- 70 to 80 degrees
Correct Answer: 50 to 60 degrees
Correct Answer Explanation: The temperature in the tunnels remained nearly stationary between 50° in winter and 60° in summer.
What was the primary material used for the tunnel lining?
- Brick
- Steel
- Stone
- Concrete
Correct Answer: Concrete
Correct Answer Explanation: The Bergen Hill Tunnels were lined with concrete, which provided strength and durability to the structure.
What was the main purpose of the concrete lining?
- To provide support for the tunnel walls
- To prevent water infiltration
- To improve ventilation
- All of the above
Correct Answer: All of the above
Correct Answer Explanation: The concrete lining served multiple purposes, providing support for the tunnel walls, preventing water infiltration, and improving ventilation.