This is an HTML version of an attachment to the Freedom of Information request 'Metadata for TD feed (Scottish region)'.

By email : request-494467-
Network Rail 
Freedom of Information 
The Quadrant  
Elder Gate 
Milton Keynes  
MK9 1EN 
01908 782405 
E xxx@xxxxxxxxxxx.xx.xx  
27th July 2018 
Dear Juhani Pirttilahti 
Information request  
Reference number: FOI2018/00834 
Thank you for your email of 28th June 2018, in which you requested the following 
‘1) Mappings of signal berths provided by C-class messages to railway signals, 
containing at least this information: 
    - TD area 
    - berth identifier 
    - signal number 
2) Mappings of data bits that appear in S-class messages to railway signals, typically 
held in a SOP file or ECS document, containing at least this information: 
    - TD area 
    - address 
    - data bit 
    - item description / signal number. 
There is no need for any additional information beyond this level. Also I would like to 
limit the search for records to cover only the Scottish region at this time.’ 

I have processed your request under the Freedom of Information Act 2000 (FOIA). 
While I can confirm that we hold the information you have requested, I am of the view 
that it is exempt from disclosure under section 31(1)(a) and section 38(1) of the 
Network Rail Infrastructure Limited Registered Office: Network Rail, 2nd Floor, One Eversholt Street, London, NW1 2DN Registered in England and Wales No. 2904587 

I am aware that we have provided similar information under the FOIA previously, 
however, due to raised security risks we are refusing your request on this occasion.  
Where information may once have appeared suitable for disclosure, any decision 
about disclosure is ultimately one of timing and we need to consider each request on 
its own merits and consider the public interest in the current climate.  
Due to the operational information contained in these files, we consider that 
disclosure in this instance would release significant information about signal 
operations into the public domain where it could be used by those who may wish to 
disrupt, interfere with or attack the workings of our infrastructure.  
The consequences of such activity would be likely to adversely affect public safety 
and endanger individuals.  
It is particularly important to remember that disclosures made under the FOIA are 
disclosures to the ‘world at large’ and any information disclosed is released into the 
public domain rather than being provided to one individual in a private transaction. 
Consequently, we have to consider the wider impact of disclosure and we cannot 
take into account the motives of an applicant even when they are well-intentioned.  
The section 31(1) and 38(1) exemptions are subject to a public interest test and this 
means that we are required to consider whether the public interest in disclosure 
outweighs the public interest in maintaining the exemptions. 
In this case, disclosure would contribute to increasing transparency and public 
knowledge about the operation and workings of this specific aspect of rail 
infrastructure and support the information already provided on our open data feeds.  
Conversely, there is little public interest in the disclosure of this type of information in 
terms of demonstrating accountability, as the information being technical and 
operational in nature, sheds no light on any factors such as public spending or 
management of the infrastructure.  
There are strong arguments around withholding the information as disclosure would 
increase the likelihood and severity of potential harm to the security of the rail 
network and wider public safety. The information requested in this case is detailed 
technical information, which goes beyond that provided by our open data feeds. We 
have sought the expert views of colleagues within signalling, and have been advised 
that their concern is that by revealing such detailed information relating to signalling, 
the nature of the information means that it could be exploited to assist in cyber-
attacks on the system. This could potentially lead to disruption of the railway network 
and create safety incidents by, for example, the mis-routing of trains. 
Network Rail Infrastructure Limited Registered Office: Network Rail, 2nd Floor, One Eversholt Street, London, NW1 2DN Registered in England and Wales No. 2904587 

The railway network has long been recognised as a potential target for terrorist and 
criminal activity. However, high-profile events such as the attack on NHS systems 
have further demonstrated that there are a number of determined individuals who will 
attempt to attack critical systems; these incidents have led us to review some of the 
information which we had previously considered safe to disclose.  
We consider that these factors outweigh all others and after consideration of all the 
relevant we consider that the balance of the public interest lies in preventing harm to 
the security of the infrastructure and in ensuring the safety of those individuals who 
work and travel on the network.  
Having considered the public interest, our decision is therefore to withhold the 
information under sections 31(1)(a) and 38(1) of the FOIA.   
I am sorry that I was not able to provide all of the information that you are seeking.  
However, I hope the explanation is helpful. If you have any enquiries about this 
response, please contact me in the first instance at xxx@xxxxxxxxxxx.xx.xx or on 
01908 782405.  Details of your appeal rights are below. 
Yours sincerely 
Joanne West 
Senior Information Officer 
Appeal Rights 
If you are unhappy with the way your request has been handled and wish to make a 
complaint or request a review of our decision, please write to the Head of Freedom of 
Information at Network Rail, Freedom of Information, The Quadrant, Elder Gate, 
Milton Keynes, MK9 1EN, or by email at xxx@xxxxxxxxxxx.xx.xx. Your request must be 
submitted within 40 working days of receipt of this letter.  
If you are not content with the outcome of the internal review, you have the right to 
apply directly to the Information Commissioner for a decision.  The Information 
Commissioner can be contacted at: 
Information Commissioner's Office 
Wycliffe House 
Water Lane 
Cheshire SK9 5AF 
Network Rail Infrastructure Limited Registered Office: Network Rail, 2nd Floor, One Eversholt Street, London, NW1 2DN Registered in England and Wales No. 2904587