What an Engineering Scale Plan shows
An Engineering Scale Plan (ESP) is the railway's master drawing of a station yard or section, drawn to scale with every feature in its true position. Engineering, signalling, traction and operating departments all work from it, and it is the base on which yard remodelling, new lines and other works are planned, checked and approved. An ESP prepared from a drone survey typically shows:
- Track: running lines, loops and sidings, track centres, and the kilometrage along the section
- Points and crossings: every turnout with its position and direction
- Platforms and passenger structures: platform lengths and edges, foot-over-bridges, ramps, shelters and station buildings
- Crossings of the line: level crossings, road over-bridges and road under-bridges
- Traction and signalling: OHE masts and portals, signals and cabins
- Bridges, culverts and drains, with their position on the section
- Buildings and land: goods sheds, service buildings, quarters, boundary walls and fencing, and the railway land boundary
- Levels: spot levels and contours for drainage, formation and earthwork
Where railways use ESPs and drone surveys
| Work | What the survey provides |
|---|---|
| Yard remodelling and new loop lines | The yard as it stands today, so new layouts fit the space, the structures and the levels |
| Doubling, third and fourth lines | A continuous strip survey of the section, with land, structures and crossings along both sides |
| Station redevelopment | Buildings, circulating areas, platforms and access roads mapped as one base for the architects and engineers |
| Cargo terminals and sidings | Site topography, approach alignment and connection to the running line |
| ROB, RUB and level-crossing works | Road and rail levels, approaches, utilities and nearby structures |
| Yard drainage plans | Ground levels and slopes, existing drains and outfalls, and the disposal point |
| Land plans and encroachments | The railway boundary laid over the orthomosaic, showing what stands on railway land |
How we prepare an ESP
- Scope and permissions: the yard limits, the chainage and the drawing standard are fixed with the railway, and flights are cleared with the station and the airspace authority.
- DGPS control: ground control points and checkpoints are set around the yard and tied to the railway's reference benchmarks.
- Drone flights: the yard is captured with overlapping images, and with LiDAR where trees or structures hide the ground.
- Processing: the images become an orthomosaic, a surface model and a terrain model with contours.
- Ground survey: rail levels, platform heights and details the drone cannot see are measured with DGPS and total station.
- Drafting: tracks, turnouts, structures and features are drawn in CAD, in the layers and scale the railway specifies.
- Checking and submission: the drawing is verified on site with railway staff, corrected and submitted, with revisions until it is accepted.
What we deliver
| Deliverable | Format | Used for |
|---|---|---|
| Engineering Scale Plan / yard plan | CAD (DWG) and PDF | Planning, approval and execution of yard works |
| Orthomosaic of the yard or section | GeoTIFF | A true-scale picture to check any detail without a site visit |
| Terrain model and contours | DTM, CAD contours | Drainage, formation levels and earthwork |
| Longitudinal and cross-sections | CAD and PDF | New lines, doubling and drainage design |
| Drainage plan | CAD and PDF | Drains, slopes and the disposal arrangement for the yard |
| GIS layers | Shapefile, KML | Asset records and land management |
DPR surveys
A Detailed Project Report is only as good as the survey under it. For railway and road DPRs we provide the survey and mapping inputs the consultant and the authority need to fix the alignment, the structures and the cost:
- Topographic strip survey of the corridor, from drone photogrammetry or LiDAR with DGPS control
- Alignment options compared on the orthomosaic and terrain model
- Longitudinal and cross-sections for earthwork and formation design
- Bridges and drainage: catchments from the terrain model, waterway sections and existing structures
- Land: the corridor laid over khasra (revenue) maps, showing the land and owners affected
- Utilities and obstructions: power lines, pipelines, buildings and other features to be shifted or avoided
- Quantities: earthwork and other quantities measured from the survey data
Why drones for railway yards
- Safety: the yard is captured from the air, so the survey team spends far less time on or beside running lines.
- Speed: one drone team captures around 5 sq km of survey data in a day, so a yard is flown in hours rather than surveyed over weeks.
- Little disturbance to traffic: flights do not need the line, and the ground work left is short and planned with the station.
- A complete record: the orthomosaic and terrain model stay on file, so later questions can be answered without returning to site.
Accuracy comes from the DGPS ground control and is proved on independent checkpoints. Read more in how accurate a drone survey is and what an Engineering Scale Plan is.
Our railway ESP work
Across two railway divisions we have prepared 93 yard and drainage plans: 61 submitted, and drainage design for 32 yards under way. Read the case study.
