Explosive ordnance surveying for marshalling and stabling yards

Assessment should begin as soon as construction sections, planned ground disturbance and operating constraints are identifiable. For track redevelopment, switch renewal, workshop access, drainage, cable civil works, overhead line foundations or site development, historical ordnance evidence, current installations, depths of ground disturbance and accessible working volumes must be brought together before tendering and construction.

Large railway yards contain rails, switches, fastenings, cables, earthing systems, signals, masts, drainage, foundations and often heterogeneous fill. These structures can strongly affect geophysical surveys. The site is therefore not assessed as a whole but divided into technically comparable subareas, deep point ground disturbances and zones accessible only after demolition.

Selection follows the target object, surface, ground conditions, interference and depth. Historical assessment establishes the grounds for suspicion; GPR, magnetometry or TDEM can investigate suitable near-surface areas. The suitability of point-specific depth investigation is assessed for piles, masts, sheet piles and boreholes. For zones that cannot be adequately surveyed, access and supplementary methods are clarified. Where explosive ordnance surveying during construction is suitable, each layer is surveyed and assessed by a specialist. Controlled excavation in layers and an additional visual inspection follow; the steps are repeated to the agreed base of excavation. Merely watching the excavator work is insufficient.

Each area receives a clear positional reference using the track, switch, chainage, construction section or coordinates. Cable and drainage routes are recorded with their width, depth, chambers and crossings; switch areas and track alignments are subdivided by construction stage and technical interference. This keeps it clear which assessment applies to which working volume.

Drawing revision, working area, surveying, equipment movement, railway safety arrangements, contacts and data handover must be coordinated before site work. A short working window must not lead to unclear survey lines or missing quality checks. Areas not reached or where data cannot be interpreted are recorded with precise positions and linked to later investigation or another measure.

Site and track drawings, switch and structure designations, construction sections, demolition stages, cable and utility drawings, drainage design, mast and borehole point lists, depths of ground disturbance, historical assessments, previous survey reports, existing reports of finds and operational and programme information are useful. Provisional documents can also be reviewed if their revision and unresolved assumptions are identified.

Official information and requirements are included with complete appendices, dates and spatial scope. In Germany, the relevant ordnance disposal service, local public order authority and, where applicable, building control are identified for the project location; operational work authorisations remain separate processes. Outside Germany, coordination is with the authorities responsible locally.

These areas are not assessed as being without anomalies. The report identifies their position, depth and the cause of the limitation and assigns a suitable follow-up measure. Necessary investigations and protective measures are specified before ground disturbance during demolition. Depending on the ground disturbance and survey conditions, additional investigations on areas accessible later, point-specific depth investigation or technically suitable explosive ordnance surveying during construction may be appropriate.

If an unexpected suspicious object is found, stop work. Do not touch, move or uncover it further. Leave the immediate area and warn others without putting yourself at risk. In Germany, notify the police on 110; outside Germany, use the local emergency reporting procedure. The competent authorities determine what happens next; a project enquiry does not replace reporting the find.

The determining factors are the size and number of subareas, existing tracks and installations, access, surface condition, methods required, number and depth of borehole or foundation positions, possessions, surveying, data quality, construction stages and documentation objectives. A reliable estimate therefore needs a structured list of working volumes and ground disturbances rather than an undifferentiated total area.