The SPRShuttle64 is the largest high capacity vehicle with seats for 64 passengers. No driver is required. It runs on solid/synthetic compound tyres and wheels and is powered by battery packs that can be easily swapped. With each pack having a minimum capacity of at least 72kWh (currently up to 100kWh) and with up to 16 packs on each vehicle providing 1.15MWh -1.6MWh of energy (potentially more), the vehicle is capable to reaching Birmingham from London in 48 minutes at a cruise speed of 155mph. This is based on using current technology. Our White Paper uses data to demonstrate this.
The wheels are enclosed with a ground clearance to base of vehicle of between 50mm and 100mm. A low ground clearance intends to improve aerodynamic performance and also lowers the centre of gravity. This is possible because the power systems and running gear are at the front and rear of the vehicle not underneath the carriage. The trackway will also be engineered to be of high quality and flat therefore allowing low ground clearance.
The tyres will be of a synthetic rubber type with an outer tread and an inner section providing some level of ride comfort. They are not intended to be pneumatic (although pneumatic tyres are proven technology and are an option). The width of the tyres and the treads will manage a balance of grip, noise attenuation and low rolling resistance. Wider tyre systems will provide better ride, whilst narrow tyre treads will reduce rolling resistance. Following feedback we believe the tyres would be between 100mm and 315mm (the width of a typical commercial tyre). If a canopy system as described below is employed over length of the trackway, wet weather performance would not be important. Cornering is not an issue either and durability is a purely economic concern, as the tyres (unlike train wheels) can easily be replaced whilst vehicle remains in service as described in our White Paper (request details below). The main argument for wider tyres would be be better braking performance in an emergency and also the transfer of wea wasr from the roadway to the replaceable tyre on the understanding that it is cheaper and easier to replace tyres than the roadway.
The track of the vehicles will be between 1.48m and 2m. A narrower track has been considered and there may be benefits to this. Wider tracking however improves stability and also space between the axles. However it is beneficial that the wheels are enclosed within the slipstreamed body shell.
We envisage the suspension to be damped using air suspension.
Whilst unsprung mass is to be avoided, in this instance there are benefits to allowing the motor and the brake disc to be installed on the axle. This will avoid transmission losses no gearing, propshaft, chain or belt system is required. The wheel motor and suspension can then be produced as an integrated unit and attached to the main body only by the swingarm linkage, suspension struts , power cable for motor and pneumatic pipes for brake.
Entry to the vehicles is via gull wing doors on either side, allowing access to seats simultaneously. This is an important part of the concept as it will reduce boarding times and departures, thus increasing capacity and shorter journey times. The seats are of a lift up design to allow access to the central aisle or other seats, but will have 3 point seat belts and will be designed for easy cleaning and maintenance and comfort. There will be limited overhead storage for coats and small bags and under-seat storage. (seats will be cantilevered to provide maximum space and fast cleaning).
All vehicles are autonomous and equipped with a variety of active and passive systems, including multiple cameras. Cameras will also be installed internally allowing real time observation of the passenger cabin and 2 way communication. They are designed to cruise at high speed with low co efficient of drag, with low resistance tyres
The SPRS64 vehicle can operate individually or in a virtual train of 9 shuttles matching HS2 200m trainsets. Buffers are installed at front and rear for low speed impacts, However the vehicles will be “virtually” entrained not mechanically linked.
The SPRS64 1.6MWh
The SPRS32 900kWh
The SPRS32 is a short version of the SPRS64 using the same components but with 32 less seats (2 passenger modules). It is designed to serve when demand is lower. It can also be customised or chartered. Like the SPRS64 it is autonomous and has side entry door and identical cabin space. in our proposal, it shares the same tractor design as the larger vehicle, However this may alter based on the cost/ benefits of reduced mass and manufacturing. the modular design with shared components is designed to allow larger production runs and therefore reduced costs.
As the service is designed to match demand the vehicles will leave when at full or near capacity or after 15 minutes or when a certain percentage of seats are taken. This will allow a continuous unscheduled service that will accurately meets demand, thus increasing both the economic and energy efficiency of the service.
The Shuttles are designed to be reversible with streamlined sections containing the power unit, batteries and control systems. These are permanently attached to passenger compartments. Because the are designed to operate on a smooth flat straight trackway they are optimised for speed not manoeuvrability. However the wheel systems do incorporate steering to allow low speed manoeuvres. These may even allow sideways crabbing and even tank turns.
However the air suspension systems not only allow good ride comfort to passengers but also allow increase in ground clearance when climbing gradients in the station area. Otherwise ground clearance is low to increase aerodynamic efficeincy. The tractor systems will utilise commercially avaible air brakes. However regenerative braking will be the primary method of slowing.
All services are autonomous with a visual systems led AI and several passive and active systems to ensure redundancy. In addtion all vehicles are linked and in communication with each other in real time, so they can be regarded as a single system. Not only does this improve safety but also allows closer distances. We suggest a 250m distance between vehicles at speed (or 4 vehicles per kilometre), but it could be less
The SPR RoboCar6/8
The SPRS RoboCar is an 6/8 seat vehicle that operates alongside the larger shuttles. It has a smaller footprint and is narrower than the shuttles. We think that an 8 seat vehicle provides more flexibility for small parties than smaller formats and allows a larger battery capacity but that the virtues of a consistent design outweigh the diminishing differences in terms of manufacturing costs, energy consumption and operational consistency. However there is no absolute rule.. it would be perfectly possible to run a 4 seat version. Our model allows for customisation and diversity (for example clients might want premium appointments (RoboLimo( or different seating arrangements.
The RoboCar would use the same power train and battery packs as the larger shuttles.
The RoboCar could be seen as a premium service and replaces the first class service in mainstream rail for the customer who requires privacy or speed as its cruising speed may be allowed to be higher than that for the larger formats Iwith a 2 metre headroom and refreshment bar . It can be pre booked and will be unlocked and opened by the customer on approach to the shuttle. Its dimensions will allow it to operate outside the High Speed trackway and may be used to service towns on the periphery of the existing route such as Bicester, Coventry and Tamworth
In addition, it would also act as a service for wheelchair users or for those with disabilities and it could also allow a 24 hour service to be maintained late at night when there is low demand.
It can be pre booked and the RoboCar can also operate on a taxi-rank basis, so departure and destination can be entirely at the choice of the customer
For a White Paper detailing the vehicles in detail including performance data and specifications email info@silkpurseroad.uk
Further Notes on Technical Aspects of Shuttle Design
Please note that we are not an Engineering Design Consultancy. Our interest is predominately in the systems integration and the economic impact of the Silk Purse Road Project. We are therefore happy to reflect on feedback and further development proposals by suitably qualified people who can provide positive and realistic solutions
However we believe that the basic principles of the vehicle design we have provided are valid with full consideration of safety and performance. For example the rapid escape or entry by emergency services of the vehicle has been accounted for in the the design of the the window systems. We believe that the large entry doors can be engineered to add to structural rigidity in the event of a rollover event. In addition bulkheads may be installed every metre, giving every passenger crush protection in the event of a rollover.
The shuttle bodies may be constructed to aerospace standards for lightness and rigidity. To reduce production costs, the shuttles are symmetrical with the use of common bulkheads. They are focussed on straight line speed with limited steering. The brake systems will be only used as point of arrival and regenerative braking will further reduce the use of friction braking systems. Low speed manoeuvring will be confined to terminuses (such as Euston) or in battery charging areas where a variety of techniques including crabbing and reverse operation can be used.
Alternative methodologies may be employed in addition to the ones tentatively described in our documentation.