2011 Headway calculation

[Nagasri.Jonna]

See attached comments

Hi PJW,

Thanq for ur valuable comments and I'll improve the calculations in the way u seggested.

[arpan_singhania]

Hi Peter,

My calculations on the layout worked out to be 4 aspect on the mainline with nominal average spacing of 1000 m.

Taking account of the derivations for Safety 0.5s<=D4<=0.75s and
Service based on D4<=(DGR/3).

I am a little confused on the branch line. Given statements points that the branch line require isolated 3 aspect signalling, but cant find the stop-stop distance. Please help me.

Thanks & Regards,

Arpan Singhania

[PJW]

Arpan,
For the branch line look at the thread reagarding the 2011 layout to see if that answers it for you; if not ask again.

Basically the headway requirement is low so that the stop-stop distance could be pretty large; in reality on a railway there may well be other reasons to have signals more frequently (protection of level crossings, pointwork etc). so one tends to place stop signal for each of these constraints (each with their own distant of course) and then just cross check that no block section is too long that it is incompatible with the capacity constraint- if it is then split section nominally in half by an intermediate signal (and its distant), but positioning sensibly (often to somewhere that makes operational sense, is easy for the technician to access etc)

Hi Peter,

My calculations on the layout worked out to be 4 aspect on the mainline with nominal average spacing of 1000 m.

Taking account of the derivations for Safety 0.5s<=D4<=0.75s and
Service based on D4<=(DGR/3).

I am a little confused on the branch line. Given statements points that the branch line require isolated 3 aspect signalling, but cant find the stop-stop distance. Please help me.

Thanks & Regards,

Arpan Singhania

[kiran218]

Hi,

I am planning to write module 2 this year. I have few doubts in that.
If train speed is 160KMPH, if we convert it in to m/s we will get it as 44.444m/s. Wether we have to go with 44.4m/s or 44m/s in the exam.
And calculator is allowed in the exam or not?

with regards,
kiran

[PJW]

Depends what you are using it for! If calculating a MINIMUM such as the braking distance then you should ROUND UP to 45; if you are using it to prove that you can achieve a headway then ROUND DOWN to 44.
Actually it is best to keep the significant figures within calculations and only do the rounding at the end.

Yes you are allowed a basic (non-programmable) calculator; it is not a test of mental arithmetic.

Hi,

I am planning to write module 2 this year. I have few doubts in that.
If train speed is 160KMPH, if we convert it in to m/s we will get it as 44.444m/s. Wether we have to go with 44.4m/s or 44m/s in the exam.
And calculator is allowed in the exam or not?

with regards,
kiran

[kiran218]

See attached comments

Hi PJW,

In Headway calculation whle decelerating the average train speed is taken as 70KMPH. on what basis it is taken as 70KMPH.

with regards,
kiran.

[PJW]

The initial speed is 140km/h.
The braking is assumed to be uniform.
Therefore the average speed during this period is the average of the initial and final speed.
Hence 70km/h.

See attached comments

Hi PJW,

In Headway calculation whle decelerating the average train speed is taken as 70KMPH. on what basis it is taken as 70KMPH.

with regards,
kiran.

[asrisaku]

Dear Railway Experienced Engineers

May I have any review for my headway calculation in 2011? please..

Best regards
Arnut