Progress Report
based upon feedback and testing from a team of testers, the steam code has been slowly refined over the last couple of months. Some additional parameters have been added to facilitate the definition of a wider range of locomotives.
Eventually some of this information will make it into the manual, but for the time being below is a heads up on some of the changes that have been done todate. This work is not completed yet so more changes are expected.
Performance Logging
To facilitate the testing it was necessary to record some of the key performance criteria of a steam locomotive at 5mph intervals, and then plot them onto a spreadsheet. This includes parameters like tractive effort, indicated horsepower, steam pressure, etc. This feature is now available to modelers who wish to compare their locomotives.
In brief to do this the following options need to be set in the OR menu:
i) Check the
Logging box on the Open Rails Menu
ii) Open the Data Logger TAB of the Options menu, and select the following options only,
Start logging with the simulation start and
Log Steam performance data
The resulting values will be logged into a csv file called Dump.csv which can be found on your desktop. The dump file can then be opened in Excel (or Open Office) as a spreadsheet, with the contents being then pasted into a spreadsheet template that has been set up to graph the different parameters.
The test spreadsheet templates are available here -
Open Rails Logging
New or Modified Advanced Parameters
Whilst a BASIC ENG file configuration will give a close resemblance to a real life model, it depends upon the locomotive conforming to "standard" ratios. However as locomotive testing over the years has demonstrated that this is not always the case. Thus it may be necessary to adjust some parameters to match the locomotives performance in OR against a published test report.
Some of the new or adjusted ADVANCED parameters added are as follows:
ORTSBoilerEvaporationRate ( x ) - can accept a value up to 30. This is to accommodate some more modern locomotives, such as the NYC Niagara, which could generate well over the standard ratio.
ORTSMaxIndicatedHorsepower ( x ) - this sets the max IHP. Max IHP typically is the lesser of the Cylinder HP or the potential Boiler power.
ORTSMaxSuperheatTemperature ( x ) - this is the maximum superheat temperature that the locomotive could achieve. This value impacts upon IHP and steam consumption.
ORTSSuperheatCutoffPressureFactor ( x ) - this adjusts the fall off in MEP as the locomotive increases speed.
For a full listing of the potential ADVANCED parameters refer to Advanced Parameters.
Test Models
In the interests of transparency, and to assist modellers in defining a locomotive, the test models used by the test team will progressively be published for comparison. These models have been tested against know test reports, and have been found to operate within an acceptable level of tolerance (nothing will ever be 100% perfect).
The first model to be tested and completed is the
NYC Niagara, which in its time was the most powerful single expansion locomotive ever built.
To Do
One thing noted during testing was the difficulty sometimes for the AI fireman to maintain a reasonable boiler pressure. A drop in boiler pressure naturally reduces the power of the locomotive. The drop in boiler pressure is predominantly due to the fact that it doesn't know when the locomotive is approaching a stop, nor when it is starting again. Consequently the fireman keeps firing until the locomotive stops, which results in excessive boiler pressure, and doesn't start firing until the locomotive commences moving, thus the boiler pressure often drops significantly until the firing "catches" up.
The possibility of allowing the firing to started or stopped by the engineer, and overrriding the AI response by "start" and "stop" key commands is currently being investigated.