The invention is directed to a method and apparatus for controlling the central spacing of track-operated vehicles, in particular railroad vehicles, along paths which are subdivided into respective individual sections for the positioning of the vehicles, in which occupied sections preferably are continuously so indicated, in dependence upon the instantaneous position of the vehicle or vehicles. Preferably, locally stationary information systems are employed, applicable in particular to railroad systems having dense train traffic and short section lengths, without a continuous information transmission between vehicles and the main office.
It is known from German Letters Pat. No. 1,176,698, in the automatic spacing control of track-operated vehicles, to subdivide the paths traveled by the vehicle into two individual sections and to indicate whether such sections are free or occupied in correspondence to the particular instantaneous position of the vehicle. A main office, operatively associated with a predetermined number of sections, in consideration of the distance between the occupied sections as well as the maximum permissible speeds within the individual sections and the operating and braking properties of the vehicles. From such information a determination may be made with respect to the continued travel of such vehicles. In order to derive this functional succession, a plurality of storage and switching systems are provided in the main office, whereby the dynamic information derived from the vehicles and the static information present in the main office are stored or further processed. The construction of such storage and switching systems must inherently provide a fail-safe operation in accordance with the universal requirements common in railroad control operations, i.e. if a component part becomes defective, dangerous information cannot be supplied to the vehicles. On the contrary, any defect should be made apparent as quickly as possible. In order to achieve these results, not only is it necessary to assure that the circuit means located on the vehicles and in the main office will function in a fail-safe manner, but also to assure a fail-safe reception and transmission between the vehicles and the main office. In railroad systems in which the path is utilized by trains with different operating properties and different speeds, as for example, on long-distance railroad lines, the expense in conjunction with the system, described in the above referred to patent, is justified for achieving the desired vehicle control.
However, where railroad systems involve dense train traffic and short section lengths, as for example, where short-distance traffic systems are involved, the expense required in the patented system would appear to be unjustifiably high, as the vehicles employing such path are usually of corresponding construction and travel at approximately the same speed between individual stations, as a result of which consideration of different vehicle speeds and vehicle characteristics is not required.
Where such a dense train succession, as results in short-distance traffic systems, the path is subdivided into as many short sections as possible in order to obtain an optimum path utilization. Again, in the application of a control system in accordance with the previously referred to patent, this would necessitate that the individual vehicles can be interrogated only at relatively large time intervals within a certain path range, or that, in order to maintain a predetermined call density, the path allocated to a main office must be kept relatively small.
As a result, a control system for short-distance traffic systems and the like should be as simple as possible, and at the same time achieve results generally corresponding to those achieved in the previously mentioned patent, i.e. that successive vehicles do not approach too close to one another but at the same time retaining as simple a construction as the particular short distance traffic system will permit. As a result, vehicles utilizing such a path need not obtain information pertinent to their continued travel, due to the similar physical characteristics and approximately equal operating speeds, nor is it necessary to utilize systems providing a dot or line-shaped information transmission between the vehicles and the main office.