View
467
Download
3
Tags:
Embed Size (px)
DESCRIPTION
"Railroad Signals" is a PowerPoint for primary and secondary students. This presentation provides a history of train and railroad signaling, as well as highlights careers in the rail industry and transportation fields. Additionally, this lesson can be paired with an "Electrical Circuits" activity.
Citation preview
RAILROAD SIGNALS
Railroad Signals
Used to prevent train collisions Collisions are a major concern as trains
travel on fixed paths A freight train travelling at 55 mph takes
over a mile to stop A train will not be able to stop before
hitting an object after the engineer sees it
Original Fixed Signals
Early signals were flags or lamps placed at a predetermined stopping distance from an obstacle
Used before stations and draw bridges
Only other control system was by timetables
Ball Signals
Began in the 1830s
Balls of different colors and shapes were raised and lowered to show “Safety” or “Danger”
Vane Signals
Began in the 1840s
Several designs
Different shapes or colors described specific situations
Block Signaling
Tracks divided into sections known as “blocks”
Used to space trains far enough apart so they could not collide
Signalmen were stationed at the beginning of each block and changed the signal
Signalmen sent telegraphs to confirm when trains passed
Widely used after 1850
Semaphores
Often used to tell an engineer they need to stop and receive a telegraph
Common in 1870s Downside was colors
were not standardized Originally white used
instead of green as green was difficult to produce
Electrical Signals
Allowed automatic signal operation from long distances
Created closed-circuit tracks by using the rails as conductors
Original idea in 1872, but at the time was not able to power a signal
Light signals Previous signals hard to distinguish from long
distances and only able to be seen during day
Position signals introduced in 1920s
Red, yellow and green lights added in 1950s
Modern Signals
Electrical currents in tracks determines if block is occupied
Block lengths may be variable and computer-generated
Signal is green if next two blocks are unoccupied
Yellow if second is occupied
Red if next is occupied
Careers in the Rail Industry• Salary: $51,000 - $61,000• Education: Bachelor’s• Experience: 0-2 years
Civil Engineer
• Salary: $56,000 - $65,000• Education: Bachelor’s • Experience: 0-2 years
Electrical Engineer
• Salary: $50,000 - $57,000• Education: Bachelor’s• Experience: 4 years
Geotechnical Engineer
• Salary: $30,000 - $39,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Welder
• Salary: $26,000 - $34,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Heavy Assembler
Civil Engineer
Designs and supervises construction projects such as airports, bridges, channels, dams, railroads and roads
Responsibilities also include estimating costs and personnel and material needs, preparing proposals and establishing completion dates
Careers in the Rail Industry• Salary: $51,000 - $61,000• Education: Bachelor’s• Experience: 0-2 years
Civil Engineer
• Salary: $56,000 - $65,000• Education: Bachelor’s • Experience: 0-2 years
Electrical Engineer
• Salary: $50,000 - $57,000• Education: Bachelor’s• Experience: 4 years
Geotechnical Engineer
• Salary: $30,000 - $39,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Welder
• Salary: $26,000 - $34,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Heavy Assembler
Electrical Engineer
Designs, tests, installs and maintains large-scale electronic equipment or machinery for use in manufacturing or power generation or transmission
May use computer-assisted engineering and design software and equipment to perform assignments
Careers in the Rail Industry• Salary: $51,000 - $61,000• Education: Bachelor’s• Experience: 0-2 years
Civil Engineer
• Salary: $56,000 - $65,000• Education: Bachelor’s • Experience: 0-2 years
Electrical Engineer
• Salary: $50,000 - $57,000• Education: Bachelor’s• Experience: 4 years
Geotechnical Engineer
• Salary: $30,000 - $39,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Welder
• Salary: $26,000 - $34,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Heavy Assembler
Geotechnical Engineer
Prepares and inspects projects involving drilling and exploration
Responsible for geological mapping, report writing, site characterization, numerical modeling and analysis of excavations/supports
Careers in the Rail Industry• Salary: $51,000 - $61,000• Education: Bachelor’s• Experience: 0-2 years
Civil Engineer
• Salary: $56,000 - $65,000• Education: Bachelor’s • Experience: 0-2 years
Electrical Engineer
• Salary: $50,000 - $57,000• Education: Bachelor’s• Experience: 4 years
Geotechnical Engineer
• Salary: $30,000 - $39,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Welder
• Salary: $26,000 - $34,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Heavy Assembler
Welder
Joins, fabricates and repairs metal and other weldable material by applying appropriate welding techniques
Interprets blueprints, specifications, diagrams or schematics to determine appropriate welding process
Inspects completed welds to determine structural soundness
Careers in the Rail Industry• Salary: $51,000 - $61,000• Education: Bachelor’s• Experience: 0-2 years
Civil Engineer
• Salary: $56,000 - $65,000• Education: Bachelor’s • Experience: 0-2 years
Electrical Engineer
• Salary: $50,000 - $57,000• Education: Bachelor’s• Experience: 4 years
Geotechnical Engineer
• Salary: $30,000 - $39,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Welder
• Salary: $26,000 - $34,000• Education: High School Diploma/G.E.D.• Experience: 0-2 years
Heavy Assembler
Heavy Assembler
Assembles fabricated parts to relatively large or heavy subassemblies and complete units
Tests and calibrates parts and mechanisms to meet tolerances and product specifications
Electrical Circuits Activity
Characteristics of electrical circuits have a closed loop have a full, circular path
Today’s activity is to build basic circuits with batteries, switches and lights
There are two ways to wire lights: Series – if one lights go out, both go out Parallel – possible for one light to work while
other does not One will give you brighter lights than the other
Helpful Hints
The green screw on the light switch is a ground, do not use this screw
Don’t attach both wires to the same end of the battery
Turn the switch to off until you are done wiring, it makes it easier to see how bright the lights are