Guideway Design
The ULTra guideway consists of any flat, drivable surface, 1.6m (5'-3") wide, with 25cm (10") kerbs that are used for optical navigation. The guideway is entirely passive, with no mechanical elements or power systems. This allows for tremendous flexibility in the design and visual appearance of both the guideway and stations.
The guideway can be constructed of different materials to suit the particular application, examples include steel with pre-cast concrete plank, fiberglass grid floor (see photo below) or simple concrete base with either concrete or plastic kerbs at ground or floor level. It is fabricated off-site, and on-site, a four-person crew can assemble two miles of guideway per month.
Minimal visual impact
Minimization of visual intrusion was an intrinsic design goal for the ULTra system. By focusing on this from the start of the project, ATS has created a system featuring the slender guideway design - only 45cm (17in) deep (see guideway specifications) - seen in the photograph on the right.
This design ensures the guideway is providing a low impact profile in the most typical view, from the side, and it is of lightweight construction due to the low overall loading requirement; British Standard for a footpath is 5kN/m2, ULTra loading is only 2.2kN/m2.
This low loading requirement is possible because the guideway is designed to meet requirements for a PRT system, and not those set out in design codes for footbridges and similar structures. Recognition of the fact that the elevated structure does not need to meet design cases for pedestrian crush loads enables a lighter, lower cost and visually more attractive design to be offered, and also allows the lightweight ULTra vehicles to run on existing building floors without significant strengthening or modification.
The photo taken at Heathrow's Terminal 5 shown below emphasises how the low loading requirements of the ULTra guideway permit a design with much lower visual impact than the elevated road sections visible around it.
An ULTra vehicle on the elevated guideway at Heathrow airport's Terminal 5.
In 2003 ATS undertook a series of passenger trials at the company’s test site in Cardiff. An independent survey assessed their response, and concluded:
- “No respondent felt that the vehicle appearance was poor, indeed the majority thought the vehicles would look excellent. The visual appearance of the elevated structure was regarded generally as good, with 40.4% rating it excellent. It is especially noteworthy that the response to the elevated track gave a notably positive response, with no definitely negative responses and only 2.6% feeling that it could be difficult.”
The possibilities for further customizing the ULTra infrastructure has recently been explored as part of the ULTra study in Bath, where an international design competition run during the summer of 2009 allowed architects and design students from across the globe the chance to suggest alternative ideas for the ULTra system's visual appearance.
A visualisation of ULTra guideway in an office park environment.
This slender ULTra guideway forms part of ULTra PRT's Cardiff test track.
Fiberglass grid running surface.