Signals

Question 1

Where will movements be governed by signals? (Hint 3 areas)

Answer 1

ABS (Automatic block signal system)
CTC (Centralized traffic control system)
Interlockings

Question 2

What is the purpose of signals?

Answer 2

Railways use signals to control movements or to improve the safety of operating trains and engines.

Question 3

Does the RTC control signals in ABS?

Answer 3

No, ABS stands for automatic block signal system. The system automatically controls the signals.

Question 4

Does RTC control signals in CTC and interlockings?

Answer 4

Yes. RTC will control signals in CTC.
Some interlockings may have a RTC or signal man controlling the signals by displaying a stop indication at specific locations.

Question 5

What information do signals tell us?

Answer 5

Tells us the certain speed to go for the block or tells the movement to stop. They also warn us and instruct us for following blocks by giving advanced signals. This is important as trains take a long time to slow or stop.

Question 6

Who is responsible for knowing the signals indication?

Answer 6

Both the conductor and the locomotive engineer. (Responsible to know the indication of a signal prior to passing it)

Question 7

What is a block?

Answer 7

A length of track with defined limits governed by block signals.

Question 8

Where are fixed signals commonly found?
(Give examples of fixed signals)

Answer 8

Commonly located above or to the right side of the track they govern.
Examples: Block signals, interlocking signals, hand operated switch targets.

Question 9

What are dwarf signals?
(Why would they be necessary)

Answer 9

Short block signals with either 1 or 2 aspects.
Used in locations where there is more than one track and the physical space is limited.

Question 10

What are mast signals?

Answer 10

Tall block signals with 1, 2, or 3 aspects.

Question 11

How is signal indication determined?
(What factors)

Answer 11

• Color of lights/aspects
• Number of lights
• Position of colors
• Lights are straight or staggered
• Type of mast (dwarf or mast)

Question 12

What would a staggered light represent? What about straight?

Answer 12

Going to a location (between locations i.e. to Irvine).
Straight means you are at a location such as, Irvine east or Irvine west.

Question 13

What factors of a signal can modify the indication?

Answer 13

If: lights are flashing, addition of letter plates, special instructions.

Question 14

What are fixed signals?

Answer 14

A signal found at a fixed location indicating the condition affecting the operation of a movement.

Question 15

May a block or interlocking signal be on the left side of the track it governs?

Answer 15

Yes, if it is required to be placed to the left of the track it governs it does not need to be indicated by the GBO or special instructions, as long as the location does not have another signal to the right of the other signaled track.

Question 16

What is another name for the lights found on signals?

Answer 16

Aspects

Question 17

What colors may an aspect be?

Answer 17

Green, yellow, or red.

Question 18

What does limited speed mean?

Answer 18

Speed does not exceed 45mph

Question 19

What does medium speed mean?

Answer 19

Speed does not exceed 30mph

Question 20

What is diverging speed?

Answer 20

A speed not exceeding 25mph

Question 21

What is slow speed?

Answer 21

Not exceeding 15mph

Question 22

Explain what restricted indication means? What should you be looking out for?

Answer 22

Speed permitting stopping within one half the range of vision of equipment and short of switches not properly lined. Never exceeding 15mph.
On the lookout for broken rails - if encountered stop immediately and contact RTC, do not go until permission given.

Question 23

What are letter plates?

Answer 23

Letter plates can be added to the signal mast to modify the indications of the signal.
1. L = limited (triangle with L)
2. R = restricting (rectangle with R)
3. A = stop or slow depending on signal attached to ( A within circle)
4. DV = Diverging (rectangle with DV)
5. M = medium (rectangle with M)

Question 24

Do letter plates apply for all indications given by a signal?

Answer 24

No, only in effect and apply to certain indications.

Example: Restricting letter plate only has significance when the lights of a signal are all red.
- it would not apply if green or yellow was on the signal. It would be a clear signal regardless if letter plate was there or not.

Question 25

What do flashing lights mean on a signal?

Answer 25

Modifies the signal indication by flashing the solid color to make the indication MORE PERMISSIVE as long as the color stays in the same position.

Question 26

What does the first part of the signal mean?

Answer 26

What is done at the current signal.
i.e.) Clear to stop signal = clear at this signal and stop at following signal.

Question 27

What does the second part of the signal mean?

Answer 27

What you prepare to do at the next signal.

Question 28

Why is red not considered a color? When might it be?

Answer 28

Red is not considered to be a color unless all the lights are red on the signal.
i.e.) If signals with green or yellow have red on them then red is only used as a dummy position.

All red = stop
Yellow/red/red = clear to stop
Yellow/green/red = clear to medium
yellow/yellow/red = clear to slow

Question 29

If you have only one light with color and it is yellow, the name will end with ___ to stop. Except when?

Answer 29

Except when restricting signal.
Also the higher you position the color on the signal the more permissive it becomes.

When it says only one color that means the others are red. Therefore, reworded it is saying all red but one yellow somewhere it will be a ___ to stop signal.

Question 30

If you only have one light with color and it is green, the name will end with ___ to clear.

Answer 30

Exception is the clear signal.
The higher the position of the color on the signal the more permissive it becomes

Question 31

When a signal has two lights with color and the color is not in the top position what does a flashing green, solid green and yellow (flashing or solid) mean?

Answer 31

When signal has two lights with color and red on top aspect.

Flashing green = limited

Solid green = medium

Yellow (solid or flashing) = slow

Question 32

When naming the colors how should you start?

Answer 32

Always start with the color in the highest position on the signal and finish the name with the lowest color.

The highest color tells you what to do at the signal and the lowest tells you how to approach the next signal.

Question 33

Name the 2 types of mast signals? What is the difference?

Answer 33

Regular and staggered.

Staggered: lights are on opposite sides of the mast.
Regular lights are on the same side of the mast.

Question 34

When do staggered and regular signals change the indication of the lights?

Answer 34

Only difference in indication is if both lights are red. The staggered will have a stop and proceed
Regular will be a stop.

All other indications are the same for both

Question 35

When reading signals with only 2 lights you can always add a light to pretend it is a 3 light signal. Where must you place this imaginary light?

Answer 35

If there is a green or yellow light in the top position the imaginary red will always go at the bottom.

If the 2 light signal only has one color in it and the color is in the bottom position then the imaginary red must always go on the top.

You must not add an imaginary red light to the staggered signal - as it could be confused as a stop signal.

Question 36

For one aspect signals what rules apply for adding imaginary lights?

Answer 36

If the light is green or yellow, add 2 imaginary red lights to the bottom.

You cannot add imaginary red lights to red signal unless it has an A plate (1 red = stop and proceed vs. 3 reds mean stop)

Cannot add imaginary to red light even if it has letter plates, they will change the meaning.

Question 37

Can you add an imaginary red to a double aspect, green dwarf signal?

Answer 37

No, double green = clear.
If you add an imaginary red it becomes medium to medium.

Question 38

Can you add an imaginary red to double aspect dwarf signals?

Answer 38

Yes, except for the following signals:
- Clear,
- Clear to limited
- Clear to medium
- Clear to slow

Question 39

What does the A plate signify on the single aspect yellow dwarf signal?

Answer 39

A = yellow is flashing = slow to stop signal

Question 40

What must be done if the signal is not properly displayed, missing, or suspected to be damaged?

Answer 40

Must be regarded as the most restrictive indication that it can display and communicate with the proper authority.

Question 41

What must be done if a block or interlocking signal with a light or multiple lights are extinguished and displays at least one green or yellow?

Answer 41

Movement reduce to a speed NOT exceeding 15mph through turnouts and be prepared to stop at the next signal.

Question 42

What is the exception to a extinguished aspect(s) and the 15mph and next signal stop?

Answer 42

If a signal displays a solid yellow on the bottom position and one or all of the remaining positions are extinguished a movement approaching such signal operates as: restricted speed, prepared to stop and prepared to comply with restricted or reduced speed.

In other words, it means restricting signal

Question 43

What must be done if a block or interlocking signal displays an indication that is more permissive then circumstances warrant?

Answer 43

Movement must stop immediately consistent with safe train handling practices. Contact the RTC or signalman for further instructions.