Niagara Falls & Old Power Station

COMPOSITION OF THE LAND
The Niagara Parks Power Station sits on a flat parcel of solid bedrock that formed nearly 430 million years ago.
The land is composed of several layers of sedimentary rock, called strata.
Even after the tunnel reached a depth of 174 feet, workers continued to dig down an additional 35 feet under the tunnel to the Medina Sandstone layer.
This was to ensure that the tunnel sat on a more solid base.

BUILDING the TUNNEL
Building a 2,200-foot underground tunnel was a significant mining task, especially in the early 1900s when construction tools and materials were much more limited than today®

THE VERTICAL SHAFT
The construction process began with the excavation of a vertical shaft halfway between the power station and the falls. Everything needed for construction had to go down or come back through this entrance shaft, including workers, equipment, building materials, explosives and excavated rock.
From the base of this underground entry point, workers continued construction of the tunnel by excavating in opposite directions. One team dug toward the power station's wheelpit, while another team dug toward the end of the tunnel where water would eventually exit into the Niagara River.

CEMENT
Cement had only been used for less than a century by the time this tunnel was under construction. The cement blend used in the tunnel was composed of one part cement powder, mixed with three parts sand and five parts aggregate. This blend was ideal to hold a lot of weight over a long period of time.
The cement was made on ground level and then pumped into the forms that lined the tunnel to fill in the desired shape. It was not used on the tunnel's arch.
HEAVY MIX RATIO
BRICKS
The ceiling of the tunnel is lined with four layers of brick that include one layer of hollow brick, two layers of solid brick and one layer of glazed brick. The tunnel boasts over 5,700,000 handmade bricks.
The top layer of brick has a glass-like coating that is durable and prohibits the accumulation of anything more than a naturally occurring slime on its surface.
Its smooth surface allowed water to pass through the tunnel without wearing down the face of the walls.

GRANITE
Granite is a durable stone with low water absorption. It was used along the last 17 feet of the tunnel, where the final drop of the tunnel meets the water of the Niagara River, due to its ability to withstand the constant flow of water passing on both the interior and exterior of the tunnel.

NIKOLA TESLA'S INDUCTION MOTOR
In 1888, Tesla delivered his first large public lecture about the benefits that alternating current could bring to the world. George Westinghouse was in favour of this new concept and was drawn to the ideas Tesla proposed. The two reached an agreement that summer and began to manufacture induction motors based on Tesla's work.
An induction motor is composed of a rotor and a stator. During operation, the stator creates a rotating magnetic field that induces a current and magnetic field in the rotor. Rotor torque builds as the rotor trails behind the rotating stator field.

UNDERSTANDING FREQUENCY
Frequency is the number of times an electrical current changes direction in a second. It is measured in hertz (Hz). During operation, the generators in this power station rotated at a rate of 25 times per second, causing the current to change direction the same number of times, or at
25 Hz frequency.
In the early years of power generation, random frequencies were used based on their convenience for powering steam engines, water turbines and the electrical generator. Frequencies could range anywhere between
17 Hz and 133 Hz. As new technology and machinery developed in the late
1800s, different frequencies were selected based on what worked best for new inventions.Read more