The Power of the TrainOps Traction Power Algorithms
Unlike most competing products, TrainOps’ dynamic simulation algorithms capture the interaction – during each simulation computational step – of trains and the power system as conditions change along the alignment. With this powerful feedback algorithm, TrainOps captures the performance loss caused by low voltages. Voltage variation at the train third rail shoe or pantograph affects train performance, so when the voltage decreases, the acceleration, velocity and location of the train are altered. Power demand of the train decreases, enabling the traction power system to partially recover from the voltage sag. Similarly, TrainOps can demonstrate the impacts on the traction power system of a line blockage (such as the opening of a movable bridge) and the ability of the system to support multiple “stacked” trains restarting.
TrainOps’ computation of energy supply and consumption by category is updated dynamically during simulation. The dark red shows energy supplied by the utility and the light red shows energy productively recovered through regenerative braking.
Competing products overstate the third rail or catenary voltages and currents, as well as the substation power demands, in simulations with dense train operations or contingency traction power configurations. This means that in comparison with TrainOps, voltages predicted by competing products are lower, and currents and substation power demands are higher, sometimes unrealistically so. The powerful TrainOps dynamic simulation algorithms avoid this issue, ensuring that simulation-based capital investment decisions are the right ones.
Very high-speed rail simulation showing maximum authorized speed (red), simulated velocity (green) and trip time (blue).
Peak and RMS currents shown for each substation in the system, along with 100% nameplate ratings, allow visual confirmation that all substations are properly sized for a new or reconfigured network.
TrainOps dynamic (while the simulation runs) display of system-wide power demand (black) with 15-minute running average power demand for utility tariff computations (red).
For new and expanding systems, TrainOps supports the detailed analyses needed to generate the most cost-effective designs, while ensuring operability under normal and contingency (degraded) conditions. Outputs include substation instantaneous, peak, and average power flows, with average statistics available over various user-selected time intervals (for comparison with “nameplate ratings” of the planned traction power system components). Other TrainOps outputs supporting the traction power design process include:
- Substation instantaneous voltage and current,
- Substation peak average and peak RMS currents for user-selected time intervals,
- Feeder RMS currents,
- Running rail voltage rise (“touch potential”) with respect to ground and stray currents.
TrainOps overlay of multiple trains’ voltage experience along a rail line, allowing fast identification of system locations in need of traction power reinforcement.
Providing a Competitive Edge When Negotiating Electricity Tariffs
Negotiating electricity tariffs requires the sophisticated “what if?” capabilities of TrainOps to ensure a successful outcome. TrainOps’ outputs include consumption and peak demand for each supply point (substation connection or rail network transmission system supply point) in the system. Should coincident demand charges (the collective demand of all substations) be considered? What about demand versus consumption charge trade-offs? How much energy will be regenerated and returned to the utility (and where)? If multiple utilities are supplying the rail network, how are demands distributed among the utilities? How can demand be shifted to the utility with the most attractive tariff structure? TrainOps can answer these questions for current and future operations in support of the best possible tariff for the rail network.
Supporting the Alternatives Analysis and Environmental Impact Statement Process
Alternative Analyses and Environmental Impact Statements need detailed train operations information. TrainOps supports these wide-ranging analytical needs, including outputs that can support:
- Operations and maintenance cost models,
- Noise and vibration studies,
- Rail-highway at-grade crossing gate down time predictions for vehicular traffic studies,
- Energy usage analyses,
- Fossil fuel emissions levels,
- “Before” and “after” trip time and throughput generation for ridership modeling purposes.
TrainOps run-time graphics show the status of each interlocking route, including green (route established), red (stacked route – route requested but occupied by another train, purple (route requested but not yet established) and gray (route being released).
Solving Traction Power Performance Issues
Traction power systems designed and constructed years ago may warrant upgrading, but what is the most cost-effective capital investment plan? TrainOps modeling can determine whether existing substations, OCS/third rail and power cables are adequate or whether some enhancements are required, particularly as service is increased and new vehicles are introduced. A thorough analysis supported by TrainOps will reveal the rail system’s strengths and weaknesses, allowing for an integrated and updated new design.
TrainOps’ powerful outputs include plots of instantaneous train voltages at third rail pickup shoes/pantographs for all trains operating on a given route. This graphic yields an overlaid voltage profile along the alignment and zeros in on traction power weak spots, TrainOps supports rapid investigation of potential solutions to traction power performance issues – adding a substation, adding a tie station/circuit breaker house, changing substation “no load” voltages, upgrading the running rails, third rail/catenary or negative return system, adding a cross-bond or even altering the train schedule (headway or train length).
Understanding the Operational Effects of Train Control
As train control systems become more complex, TrainOps can provide an understanding of their operational impacts – before they are placed in service. Whether a wayside, cab, or wayside with cab signaling system, TrainOps can model the site-specific headway constraints enforced by the system. TrainOps also supports the analysis of Positive Train Control systems – stand-alone or overlaid on top of a conventional signaling system. The software supports different brake rates for the same train consist, depending on the type of train control system and type of enforcement.
Terminal track occupancy diagram showing simulated times (above the line) and scheduled times (below the line) with train classes distinguished by color.
TrainOps’ Modeling Flexibility
Mainline railroad, very high-speed rail, monorail, Automated Guideway Transit (“people movers”), streetcars, light rail and heavy rail traction power systems, as well as electric trolley bus systems, can be simulated. TrainOps supports completely flexible rail network/traction power system modeling with all system components represented individually in the model. A typical simulation may include the following variations in rail network infrastructure and operational attributes:
- Changes in gradients, curvature and speed restrictions (including different speeds for different train classes) as function of individual track or route,
- Substations of different input voltages, output voltages, and power ratings,
- Changes in third rail sections, overhead catenary, or trolley wire along the alignment,
- Detailed representation of the positive circuit with jumpers between tracks and conductor section breaks,
- Changes in running rail characteristics,
- Detailed representation of the negative return circuits with cross-connections between rails. TrainOps includes series resistances due to impedance bonds and shunt resistances between the running rails and ground, supporting output of running rail-to-ground voltages and stray currents returning to system substations,
- AC feeders and return circuits, positive and negative DC feeders of different cable types, resistances, and lengths,
- Different vehicles and train make-ups (as multiple units or locomotive-hauled trains), including homogeneous and heterogeneous consists,
- Different passenger station stopping patterns for each train trip, such as express, local and skip-stop train service,
- Different passenger station dwell times for each station and train,
- A different loading pattern for each train as it travels along the alignment making possible, for example, simulation of fully loaded trains in downtown areas and partially loaded trains in suburbs,
- Static loads representing stationary trains in storage yards,
- Outages of substations, feeder breakers, and feeders,
- User-selectable time step, ranging from coarse computations for rapid-response planning studies to fine computations for sophisticated engineering analyses.
TrainOps time-distance string chart for rapid transit service ramp-up, including color coding by track and representation of midline turnback locations.
Powerful Automated Routing
TrainOps performs run-time train routing that finds the best path for each trip through your rail network. Unlike competing products, which force users to manually route trains or try thousands of routing combinations before settling on a workable solution, TrainOps’ powerful “look ahead” algorithms route trains as a dispatcher would – while they move through the network. Automated routing capabilities in TrainOps include:
- No limit on the number of Train Classes in the simulation, each with different levels of dispatching priority,
- Automatic terminal route selection, including turnback and yard layup/put-in considerations,
- Automatic routing through the rail network, including traffic directionality, reversal time and fleeting considerations,
- Support for track outage planning, including platooning of movements to maximize system velocity,
- Automatic selection from among multiple yard leads if one is blocked or is about to be used in a different direction.
TrainOps run-time graph of voltage, current and power as a function of simulated time for a user-selected substation.
Speeding the Model Development Process
TrainOps was specifically developed to enable comprehensive modeling and studies of ac- and dc-electrified railroad and transit train operation, as well as operations of fossil fuel-powered trains. The program provides user-friendly inputs (including the ability to “cut and paste” from spreadsheets) for all relevant system and rolling characteristics, including:
- Route alignment data, including track gradients, horizontal alignment and speed restrictions (which can differ by train class),
- Passenger station locations,
- Train data, including weight, dimensions, propulsion system characteristics, and braking system parameters,
- System train control data, including wayside signaling, cab signaling and Positive Train Control inputs (optional),
- Electrical power supply system data, comprising traction power supply substations and tie stations (circuit breaker houses),
- Railroad sub-transmission system (optional),
- Electrical distribution system, such as overhead catenary, trolley wire system, or third rail system, and substation feeder cables,
- Operations data, such as train consist sizes, train consist manipulations at terminals/yards, operating plan (timetable) inputs, passenger station stopping pattern, and station dwell times.
Supporting Rail Networks of All Sizes
TrainOps is developed using modern software technologies and development methods. There is no inherent software limit on the size of the rail network, the complexity of the traction power system, the number of trains that can be simulated, or the duration of simulation. In short, it can model any rail network of any size.
TrainOps trip graph for an ATC cab signal system with civil speed enforcement. Graphs are dynamically updated while the simulation runs (note the right end of the green plot shows the current location of the train; the right end of the purple plot shows the limit of dispatcher route establishment for this train trip).
TrainOps is a software product developed by the rail systems and software professionals of LTK Engineering Services, an employee-owned company. With more than 200 rail professionals specializing in vehicles, traction power, train control, infrastructure and operations, LTK brings unparalleled technical expertise to the simulation of rail networks.