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Engineering Design

DC Traction Substation

We undertake and fulfil all design requirements for DC traction substation and Track Paralleling Hut (TP Hut) including:

  • TP Hut-to-Substation conversion;

  • HV switchgear renewal;

  • Rectifier-transformer renewal complete with new main DC circuit breaker; 

  • DC switchgear renewal;

  • Procurement supply specifications for substation equipment;

  • SCADA/ RTU interface requirements;

  • Witness of Factory Acceptance Testing (FAT);

  • HV switchgear, DC switchgear and rectifier protection calculations;

  • Negative Short Circuiting Devices (NSCD) for safer isolations.

Electric Track Equipment

We undertake wide range of ETE designs from power supply enhancements, ETE designs associated with S&C renewals, signalling upgrade, platform extensions etc.

Typical deliverables include:

  • Comprehensive Track Diagrams (CTD) and Isolation Diagrams;

  • Conductor rail layouts;

  • Conductor rail gapping analysis;

  • Provision for Controlled Track Switches (CTS) and Track Disconnectors (TD);

  • Negative bonding plans;

  • Conductor rail heating designs;

  • DC stray current analysis and mitigation.

SCADA Interface

We provide specifications and design interfaces for all Supervisory Control And Data Acquisition (SCADA)/ Remote Terminal Unit (RTU) works. Our engineers have experience in modern RTU as well as electro-mechanical supervisory systems. Typical deliverables include:

  • SCADA/ RTU equipment procurement specification;

  • I/O schedules;

  • Staged Operations Diagrams for SCADA implementation;

  • Cable and termination schedules for the interface between switchgear, plant and SCADA/ RTU;

  • Implementation strategy;

  • Review of SCADA Electrical Control Room (ECR) graphics.

Low Voltage Alternating Current (LVAC) 

We are experienced in the provision of designs for substation domestic services including heating, lighting, emergency lighting and small power.


Typical deliverables include:

  • Specification of equipment;

  • Distribution Network Operator (DNO) supply and earthing arrangement;

  • Amtech low voltage electrical calculation software is used to determining type of protection device, cable sizing, voltage drop, protection coordination, Prospective Earth Fault Current (PEFC) and Prospective Short Circuit Current (PSCC) calculations;

  • Auxiliary transformer and LVAC panel alterations.

The designs ensure the electrical installaion is compliant with BS7671 IET Wiring Regulations.

Lighting Design

Rail Power Solutions have undertaken various lighting designs to meet lighting requirements internal and external to substations and Track Paralleling Huts (TP Hut) and at train stabling depots and sidings. The exact requirements for the lighting design is understood from the outset ensuring the Client's requirements are met in full. 

Lighting designs are undertaken using DIALux or RELUX lighting calculation software, which provides accurate indoor and outdoor lighting calculations and realistic visualisations.

All our lighting designs conform to:

  • RIS-7702-INS;

  • GI/GN7520;

  • RT/ENGP/06/22;

  • BSEN12464-2:2007.

HV Feeder Renewals

We are able to provide outline and detailed designs, which fully detail all requirements for the renewal of HV feeder and pilot cables.


Typical deliverables include:

  • 66, 33, 22 & 11kV HV feeder cable renewals;

  • Pilot cable renewals (electro-mechanical and modern SCADA systems);

  • HV feeder and pilot cable diversion works;

  • Hydraulic & Alarm (H&A) Studies;

  • Pilot cable supervisory system design (electro-mechanical and modern SCADA systems);

  • HV cable end box modification designs to accept disconnectable type HV terminations.

Depots and Sidings

We have extensive knowledge and experience in the design of new depots, upgrade to existing depots and ETE designs for depots and sidings.  We can identify all details associated with the upgrade required, including:

  • Load assessments calculations and recommendations;

  • Substation capacity assessments;

  • ETE rating assessment;

  • DC sectionalisation requirements for DC electrical section;

  • DC shore supply design including Emergency Power Off (EPO), contactor panel, warning lights, overhead power and control busbars, Pendant Switchable Trolley (PST) design;

  • AC shore supply designs;

  • Depot Protection System (DPS) interface design;

  • Isolation instruction alterations (including staged works).


We undertake detailed site surveys to identify the existing earthing and bonding arrangements at substations and Track Paralleling Huts (TP Hut). From this, we are able to provide comprehensive earthing designs for the site. In addition, we undertake the following tests:


  • ‘Fall of Potential’ test to determine existing system earth;

  • ‘Double Clamp Stakeless’ method to determine local earth;

  • Soil resistivity measurements using the ‘4-Pole Wenner’ method;

  • Soil analysis test.


Our earthing designs are undertaken using the ‘CDEGS Earthing Design’ software package to determine, rise of earth potential, touch potential and step potential. In addition, we identify how to prevent and reduce transferred potentials.

Overhead Line Equipment (OLE)

Rail Power Solutions Engineers are experienced in OLE Power Distribution designs. Design capabilities include:


  • Design of Independent Feeders for Auto Transformer Feeder Stations;

  • Design of 25kV AC Feeder Stations (FS), Track Sectioning Cabins (TSC) which includes the design of 25kV AC switchgear;

  • Equipment layout, wiring diagrams and Low Voltage (LV) distribution design;

  • SCADA interface.

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