User interface of computer workstation for railway signals - using second computer performing checkback on possibly dangerous routes in text form and requiring acknowledgement

The user interface uses a display (B) on an X-terminal (3) which is built up from extraneous information (i1) by a first computer (1) while the checking of the operational state is guaranteed by a second computer (2). The first computer processes commands (4) from a keyboard or mouse. The second computer forms a process image (Z) from other extraneous information (i2) for safety checking by examination of the state of all elements which could influence the acceptability of the critical command. USE/ADVANTAGE - In railway signalling centres, more flexible system allows fully graphic display instead of the conventional two-channel colour visual presentation. Greater reliability.