RIBA Overhead Line Structures Competition
Questions and Answers
Q1. Should we be proposing solutions for both single mast cantilever solutions and
also portal frame gantries? The sample drawings show both, but the technical spec
only mentions single track cantilever masts.
A1. Yes a design for both the cantilever and the gantry should be proposed. The
technical spec is relevant for both types of structure.
Q2. If portal gantries are required, what is the maximum span required and the
maximum number of tracks to be covered by a single gantry?
A2. The purpose of the portal frame is to span multiple tracks where there is
insufficient space to install a standard cantilever mast. Portal frames are used at
junction where additional tracks are present. The design of the portal frame should
be scalable, like the existing design shown on the competition drawing where the
size of the lattice beam is increased as the span increases. For the purpose of the
competition, the portal frame should be designed to span 4 tracks, 20m mast centre
to mast centre.
Q3. We are planning the layout of our A1 sheets for our design proposal.
It is not possible at the 1:20 scale requested in the Competition Instructions to
illustrate a two-track layout twin OHLE mast configuration in both transverse & long
elevation on one A1 sheet.
It is only possible at 1:20 scale on one sheet to show a single mast (plus single track)
in both transverse and longitudinal elevation.
Since the most prevalent configuration for HS2 is twin track, and in light of the above
constraint, please could you advise us in more detail on both the track configuration
and elevation scales that you deem appropriate.
A3. If you wish to demonstrate a twin track configuration then you may choose an
alternative scale to suit providing sufficient detail can be seen.
Q4. Cost Summary: Page 11 of the Brief states that a Cost Summary is required as
part of the 500 word written design statement. We are working on the basis that this
is entirely separate from the 'Application Finances' cost breakdown in Section 6 of the
application form. Please could you confirm that our understanding is correct.
A4. The cost summary is a breakdown of costs for the proposed design and not
related to the development stages of the competition.
Q5. For 'Application Form' Sections 4 (Description of Design Idea) and 5. (Technical
Team & Expertise), would it be possible to provide a response to these sections by
means of a separate appendix document - limited of course to 500 words for the
'Description of Design Idea'. We are asking this question, because we assess that it
will be very difficult to accommodate 500 words, plus the Cost Summary, plus a
description of our team and expertise on only 2 sides of A4, as contained in the
application form.
A5. An appendix may be included if deemed necessary however this should not
exceed an additional 2 singles sides of A4.
Q6. We are making the assumption that we are to design three different types of
mast, each of which correspond to the diagram which is part of the pack.
a.
b.
c.
The Heater Mast TX
Smaller single cantilever mast.
The lattice structure which bridges two tracks.
We are making a completely different pattern of structure which assumes all of the
existing (as shown) wire dimensions, tensioners and proximities from each other.
We don’t see any specific request to show anything different from this but the brief is
unclear. Perhaps you could add clarification on these points?
A6. You are not required to design a points heater TX Mast.
Q7. Design of end structures and ‘turning’ structures, what’s the meaning of ‘end’ and
‘turning‘ structures ?
A7. The term end structure has been used to describe the anchor structure which
supports the tensioning device for the overhead conductors. This will require a
backstay unless it can be demonstrated that the anchor mast is self supporting.
You are not required to design this type of structure at this stage of the
competition.
Q8. A written design statement (maximum of 500 words) in support of the
submission including a cost summary, the cost summary is the cost estimation for the
Stage 1 work we assume. And not a manufacturing cost estimation for the 1:1 design.
A8. The cost summary should be a cost breakdown for the actual
design/manufacture and not the modelling work/stage 1 development of designs.
Q9. Does the phase one budget cover the professional fees of the team?
A9. Costs for the phase 1 development are those incurred in producing the model
and developing the design. The team may therefore include their time for this
however should bear in mind that value for money will be a consideration at the
judging of stage 1.
Please also see the additional statement regarding the application finances and
modelling.
Q10. With regard to the pricing of the 1:10 model should transportation cost be
factored?
A10. Please see additional statement.
Q11. Regarding the 1:10 model, how keen is the jury on material accuracy?
A11. Material accuracy in modelling is not a requirement however an indication of
the preferred construction materials should be demonstrated.
Q12. Can you direct us to any specific reference documentation which indicates the
current cost of overhead line structures.
A12. The existing structure design is based on the use of standard steel section
(universal column) with welded base plates. The masts are pre-drilled for fixing
cantilevers and then hot dipped galvanised. The cost of a standard mast is between
£1000-£1200.
Q13. Would the Jury accept a separate a4 cost breakdown alongside the a1 panels?
A13. The cost breakdown should be included in the separate written design
statement (maximum 500 words).
Q14. Are there any painting or material reflectivity restrictions?
A14. There are no specific requirements; the current structures are dull grey in
colour (weathered galvanised steel). Structures with highly reflective surfaces
would have to be reviewed to ensure that reflections do not impact on signal
sighting and driver sight lines.
Q15. Can there be any alterations or additions to the overhead lines to increase
tension?
A15. No additions or alterations to the lines - The conductor tension is as stated in
the design brief.
Q16. Could the details of a competent model maker be forwarded to us, please?
A16. Please see additional statement.
Q17. Must I design three Aesthetic Overhead Lines Structure?
1 portal frame
2 cantilever masts
3 mast with points heater tx
A17. You are not required to design a points heater tx mast at this stage of the
competition, but consideration should be given as to how your proposed design
could be adapted to meet this type of support structure.
Q18. STAGE 1 – ‘Two additional designs around additional “end” structures’ – please
clarify what is meant by “end structures”.
A18. The term end structure has been used to describe the anchor structure which
supports the tensioning device for the overhead conductors. This will require a
backstay unless it can be demonstrated that the anchor mast is self supporting. You
are not required to design this type of structure at this stage of the competition.
Two additional designs will only be required in the final stage 2 when up to four
schemes are selected for the prototyping phase.
Q19. Should the design consider the need to support booster transformers/pointheating transformers?
A19. See response to Q17.
Q20. We assume that the design should incorporate the -25Kv feeder arrangement.
A20. Yes that is correct.
Q21. For this application submission, are we expected to propose designs for both
gantry and cantilever structures?
A21. Yes that is correct.
Q22. Are there more technical drawings available for applicants? Cad drawing files
would be helpful to understand all necessary clearances and measurements.
A22. Not at this stage of the competition.
Q23. Are there more site information available for applicants? Site plans and site
images along the HS2 route would be very helpful.
A23. The requirement is for a generic design that can be applied in various
locations.
Q24. The brief mentions a document EN 50119 2009+A1 2013 for general issues
regarding the design of current electrification structures. Is this document available
to applicants?
A24. This document can be purchased online from the British Standards Institute.
We are unable to provide copies of the standards due to copyright and our current
licence agreement.
Q25. Stage 1 should generate a model and two additional designs of end structures
and turning structures, correct? 'The Challenge' in the brief includes this in Stage 2.
A25. The brief has now been amended to make this clearer. To clarify - designs for
the end and turning structures will only be required at the prototyping phase for
the finalists (up to four).
Q26 to Q30 to relate to Cost Estimate
Q26. If two additional designs to be made during Stage 1, could we include
engineering consultant fees in the cost estimate for the application?
A26. Please see response to Q9 and Q25.
Q27. For the international applicants, can travel expenses for the interview in UK be
part of the cost estimate?
A27. Travel expenses will not be covered however video conferencing facilities can
be made available to any international candidates where it is not feasible for them
to attend an interview in the UK.
Q28. If we utilize RIBA's help for making a model in stage 1, do we exclude modelling
expense from the cost estimate?
A28. Please see additional statement.
Q29. If the cost is part of the judging criteria as described as 'Value for Money will be
a criterion in the assessment of applications' in the brief, is it to the applicants
advantage to lower the cost for their expenses?
A29. Please see additional statement.
Q30. The application guidance says, 'Itemisation of costs and methods of calculation
may be requested to support the application at a later date.' When can this be
requested?
A30. Details will be provided to successful applicants who are shortlisted to help
them with the modelling stage.
Q31. Submission requirement includes 'one visual image of the structures in their
setting' in two different resolution versions. Can this image be same as the one used
in two design sheets? Can we submit multiple images?
A31. Yes the key visual image for publicity should be one that is used on the design
sheets. It would be better if only one image is selected as there will be space to
only show one representative publicity image on the competition website gallery.
Q32. Is an animation format of visualization allowed as a part of submission?
A32. No an animation is not permitted and your submission should be in the format
as stated in the application requirements.
Q33. The application guidance includes two sections about the information of the
team: '2. contact details of lead applicant/organization' and '5. technical team and its
expertise.' By technical team, do you mean all design team members including
structural consultants?
A33. Yes
Q34. The images of the landscape the line will pass through, were these intended for
our use in order to photomontage our own proposals onto? If so, can we have the
original images, without a proposed design already in them in order to use?
A34. These photos were just examples and you are not required to photomontage
your proposals onto them. For the next stage the ten shortlisted candidates will be
provided with the context in which to model their designs.
Q35. I presume that we are assuming that the line is 25 kV AC line and so all power
remaining above head? Including the earth being a wire and not a rail?
A35. This is a 2 x 25kV system, including earth and traction return conductors.
Q36. Why is the negative feeder wire (earth wire) not shown on the portal frame
structure section provided? Is it / the insulated supports to hold it, needed on this
structure?
A36. Typically, the 25kV negative feeder wire will be supported by post insulators
mounted on top of the portal frame. A revised drawing will be issued to provide
additional information.
Q37. What is the standoff radius to the feeder wire?
A37. This detail is shown on the competition design information.
Q38. Can we have minimum and maximum dimensions of the contact wire from the
mast?
A38. Nominal minimum height is 5080mm. Maximum height is 5300mm (BS EN
50367)
Q39. Can we have minimum and maximum dimensions of the mast from the rail?
A39. The minimum distance is governed by the structure gauge, which is 1.575m
(from track centreline) for UIC GC gauge. However, on high speed lines masts are
generally located at least 3.5m from the track centreline to provide an indication of
the minimum distance that staff must maintain to the track. The maximum
distance is not defined as this is governed by the space available at each location.
The general design of existing support structures is scalable to cater for the
additional torsional load applied to the structure as a result of increasing the mast
to track spacing.
Q40. Can we have minimum and maximum dimensions of the contact wire from the
track?
A40. This detail is shown on the competition design information.
Q41. Can we have minimum and maximum dimensions of the S&T LV cables from the
track?
A41. Not required to design the support structure
Q42. What is the standoff radius to the feeder wire?
A42. This detail is shown on the competition design information.
Q43. Can we have minimum and maximum dimensions between the LV and HV
cables?
A43. Not required to design the support structure.
Q44. Can we have minimum and maximum dimensions of the HV cables from the
track?
A44. Not required to design the support structure.
Q45. What is the minimum distance between the track and the access path?
A45. Not required to design the support structure.
_____________________________________________________________________
Additional Statement regarding Application Finances and the Modelling
Stage
Please note that an exciting opportunity has now arisen to showcase the shortlisted
model designs for a month at the National Railway Museum in York.
Initially it was expected that competitors would source their own model makers,
however due to the requirements for exhibitions at the National Railway Museum
(NRM) it has been recommended that all models are produced by the same model
maker to ensure consistent standards and robustness.
Due to this change in the anticipated format the ‘Application Finances’ section of the
Application Form will no longer need to be completed by the deadline. Once the
shortlisted designs have been selected, the authors will then be issued with the
revised ‘Application Finances’ form which will include further information regarding
the modelling stage and the recommended model maker.
Please find attached an amended application form which reflects this change.