Aspect Sequence exercise

[onestrangeday]

Hi PJW:

Sure, I've understand what you have said. Thanks for taking time to review and give comment on my work.

As from your explaination you have mentioned that dashed line and 'MAR' shown on the aspect sequence depicts the meaning of approah release. (so is this the UK practice right? I mean the legend of using dashed line and 'MAR depicts the meaning of approach release)

What do 'MAR' stand for?

M-?
AP-approach release?

Here is my attachment to compare presentation to your orginal.
I think I had too large a file size before.

Note that I have assumed that signals 11,15 and 13,17 all exist.
Actually because there are slower speed diverging routes from 15 & 17 it isn't enough just to say the rear signals cannot clear until the forward signals are off, as these themselves would have to be approach released.
Potentially could make the condition as "ready to clear" rather than "off" but that is a complication best avoided at this stage of learning.

Hence I have given 11 & 13 yellow aspects which would themselves need to be approach released (but note that their Greens would be shown when 15/17 showing Green and would NOT be approach released) because of the underbraking. However as stated in earlier reply, better not to have all those signals.

Conversely since 15/17 to 21 is overbraked then I have assumed that for the branch that the 3 aspect signals do not show their yellow and that there is an extra signal 19 to act as a distant for 21.

Modified attachment to show the A/R for 11 & 13 more clearly

[PJW]

Approach Release lines must be vertical as they go from the original aspect (normally Red) to the final aspect(s) and drawn closely on the approach side of the signal which is changing.

They must be clearly distinguished from the aspect sequence liines which go from one or more of the "next signal's" aspects to dictate the aspect shown on the signal(s) on the approach. If you never drew these vertical then there would be no need to make the aspect sequence lines dashed (and if drawing by hand by ink pen on a linen or plastic negative it just makes it harder and slower and less neat). However with computer depiction it is just as easy to draw as dashed line so it is a good idea to do so, particularly if there are other vertical lines which mustn't get confused.

I would recommend drawing as dashed for exam purposes, but you will not find a standard to instruct that.

M= Main
A= Approach Release
R= from Red.

There are other forms of release-
MAF = Main Aspect Free (i.e. No Approach Release)- only written when there might seem to be a need for Approach Release but actually isn't- for example where there are diverging routes but of equal speed to the main route.

MAY-YY = Main Appproach Release from Yellow with the signal next in rear displaying Double Yellow

MAY-FA = Main Appproach Release from Yellow with the signal next in rear displaying Flashing Aspect (Flashing Single Yellow)

It is actually often superfluous to mark MAR, MAY-FA etc on the chart against the approach release, since it is obvious from other things on the drawing anyway. Normally would annotate to define which tracks have to be occupied for what time to give the condition. I marked to make more clear to you. However in exam condition, probably a good idea to add since it shows understanding. Also helps distinguish from other reasons (i.e other than signalling of diverging junctions) for holding a signal at danger until train is close, which are:
a) lack of braking to next signal (as in the example)
b) only a short "restricted overlap" availabale beyond the following signal.

Hi PJW:

Sure, I've understand what you have said. Thanks for taking time to review and give comment on my work.

As from your explanation you have mentioned that dashed line and 'MAR' shown on the aspect sequence depicts the meaning of approah release. (so is this the UK practice right? I mean the legend of using dashed line and 'MAR depicts the meaning of approach release)

What do 'MAR' stand for?

M-?
AP-approach release?

[onestrangeday]

Hi PJW:

Thanks for your reply.
Ok, I see how it works now.

Approach Release lines must be vertical as they go from the original aspect (normally Red) to the final aspect(s) and drawn closely on the approach side of the signal which is changing.

They must be clearly distinguished from the aspect sequence liines which go from one or more of the "next signal's" aspects to dictate the aspect shown on the signal(s) on the approach. If you never drew these vertical then there would be no need to make the aspect sequence lines dashed (and if drawing by hand by ink pen on a linen or plastic negative it just makes it harder and slower and less neat). However with computer depiction it is just as easy to draw as dashed line so it is a good idea to do so, particularly if there are other vertical lines which mustn't get confused.

I would recommend drawing as dashed for exam purposes, but you will not find a standard to instruct that.

M= Main
A= Approach Release
R= from Red.

There are other forms of release-
MAF = Main Aspect Free (i.e. No Approach Release)- only written when there might seem to be a need for Approach Release but actually isn't- for example where there are diverging routes but of equal speed to the main route.

MAY-YY = Main Appproach Release from Yellow with the signal next in rear displaying Double Yellow

MAY-FA = Main Appproach Release from Yellow with the signal next in rear displaying Flashing Aspect (Flashing Single Yellow)

It is actually often superfluous to mark MAR, MAY-FA etc on the chart against the approach release, since it is obvious from other things on the drawing anyway. Normally would annotate to define which tracks have to be occupied for what time to give the condition. I marked to make more clear to you. However in exam condition, probably a good idea to add since it shows understanding. Also helps distinguish from other reasons (i.e other than signalling of diverging junctions) for holding a signal at danger until train is close, which are:
a) lack of braking to next signal (as in the example)
b) only a short "restricted overlap" availabale beyond the following signal.

Hi PJW:

Sure, I've understand what you have said. Thanks for taking time to review and give comment on my work.

As from your explanation you have mentioned that dashed line and 'MAR' shown on the aspect sequence depicts the meaning of approah release. (so is this the UK practice right? I mean the legend of using dashed line and 'MAR depicts the meaning of approach release)

What do 'MAR' stand for?

M-?
AP-approach release?