Rules query RSSB

[Pilotman]

Hi guys

Can someone shed any light on the following rules as per RSSB:-

When AWS defective/isolated TPWS ok the max speed is 40mph
When AWS defective/isolated TPWS ok and now DSD isolated 60mph

Why is when you have 2 safety systems, you can go faster? i understand this can be unit specific but still makes no sense why you can increase your speed.

Thanks

 

[Interlude]

I think this is is a typo or error. These are the rules surrounding AWS and the DSD as I understand them:

The max speed when AWS is defective is 40mph, unless there is a competent person present in addition to the driver, in which case line speed is permitted. If the DSD is also isolated, the max speed is 40mph and there must be a competent person present. If just the DSD is isolated/defective, max speed is 60mph.

 

[coxxy]

Like most of the rule book the wording for this bit is quite ambiguous.. simply put dsd/DVD isolated then 60 mph.. aws/tpws isolated then 40mph.. if both isolated then would obviously be 40 mph..

This obviously changes if you have a competent person in the cab.

 

[Supercoss]

Page 30 (lower) page 31 here
https://www.rssb.co.uk/rgs/rulebooks/GERT8000-TW5 Iss 7.pdf
=
If no competent person is immediately available, and TPWS is
working whether AWS is working or not, you can proceed at a
speed not exceeding 60 mph (100 km/h) to the location where a
competent person is available or to the location where the train can
be dealt with.
Key bit is here
b) If AWS and TPWS are not working correctly
If the DSD becomes defective or you need to isolate the vigilance
equipment and the AWS and TPWS are not working

AWS and tpws *not* aws OR tpws

 

[GB]

AWS and tpws *not* aws OR tpws

Part A deals with "or" and Part B deals with "And".

Part A states you can travel at 60mph with the DSD isloated and TPWS working "whether AWS is working or not". So if AWS isn't working it says you can travel at 60mph.

Part B says if all three systems isolated your not to move until competent person arrived and then only at 40mph.

8.4 When in service
a) If AWS or TPWS is working correctly
If the DSD becomes defective, or you need to isolate the vigilance
equipment and the AWS or TPWS is operating correctly, you must:
• stop the train immediately
• tell the signaller
• not move the train until instructed to do so
• carry out the instructions given.
If permission is given for the train to proceed, you must apply the
following conditions.
If no competent person is immediately available, and AWS is
working but TPWS is not working, you can proceed at a speed not
exceeding 40 mph (65 km/h) to the location where a competent
person is available or to the location where the train can be dealt
with.
If no competent person is immediately available, and TPWS is
working whether AWS is working or not, you can proceed at a
speed not exceeding 60 mph (100 km/h) to the location where a
competent person is available or to the location where the train can
be dealt with.
When a competent person has been provided, you can proceed at
normal permissible speed to the location where the train can be
dealt with.
b) If AWS and TPWS are not working correctly
If the DSD becomes defective or you need to isolate the vigilance
equipment and the AWS and TPWS are not working correctly, you
must:
• stop the train immediately
• tell the signaller
• not move the train until a competent person is provided
• carry out the instructions given.
09/16
TW5 issue 7 final_TW5 05/08/2016 11:00 Page 32
Uncontrolled When Printed
Document comes into force and supersedes GERT8000-TW5 Iss 6 with effect from 03/12/2016
section
31
When the competent person has been provided, you must proceed driver
at a speed not exceeding 40 mph (65 km/h), to the location where
the train can be dealt with.

 

[Tomnick]

Part A states you can travel at 60mph with the DSD isloated and TPWS working "whether AWS is working or not". So if AWS isn't working it says you can travel at 60mph.

But TW5 4.5 states that the maximum speed is 40mph with the AWS defective/isolated and no competent person provided, which is presumably the slight contradiction referred to. With AWS isolated, DSD defective but TPWS ok, the maximum speed would still be 40mph because TW5 4.5 still applies, even though a 60mph maximum speed has been imposed for another reason.

 

[Pilotman]

Thanks guys i have created the query with RSSB which is is motion at the moment, just wondered what other views were as correctly said it does seem a contradiction.