Q-1. “To what railroads do the Rules, Standards, and Instructions apply?”

A. The Rules, Standards, and Instructions apply to all railroads that operate on standard gage track that is part of the general railroad system of transportation, except as provided in paragraph (b) (see section 236.0).

Q-2. “How does the type of signal system affect the maximum allowable train speed?”

A. Section 236.0 prescribes that a block signal system, or a manual block system permanently in effect, must be in effect for freight trains to operate 50 or more miles per hour, and/or passenger trains to operate at 60 or more mph. An automatic cab signal, train stop, or train control system must be provided where any trains operate at 80 or more mph.

Q-3. “What would be some examples of being in violation of section 236.4 - interference with normal functioning of device?”

A. Section 236.4 states: “The normal functioning of any device shall not be interfered with in testing or otherwise without first taking measures to provide for safety of train operation which depends on normal functioning of such device.”

In simple terms, interference includes such as where a device or component of a signal or train control system is worked on, altered, adjusted, repaired, replaced, or tampered with, without providing for the safety of train operations that may be affected by what was done. Specific examples would include such as: improperly adjusting a switch circuit controller; repairing a signal mechanism and leaving a jumper wire on that falsely energizes a circuit; replacing the fouling wires on a switch but forgetting or failing to permanently apply them to the rail; or conducting a wiring change where an error is made but the necessary testing is not conducted to catch and correct the error.

Q-4. “What railroads are required to have a software management control plan?”

A. Section 236.18 requires that all railroads must develop, adopt, and implement a software management control plan to assure that software used in their processor-based signal and train control equipment in service is the version intended by the railroad to be in service at each location. Therefore, any railroad that has any processor-based signal or train control equipment must have such a plan.

Each railroad must develop and adopt a software management control plan on or before December 6, 2005. Each railroad commencing operations after June 6, 2005, is required to adopt a software management control plan prior to commencing operations. Each railroad is then required to have its software management control plan fully implemented no later than 30 months after its adoption. The deadline for implementation is June 6, 2008. Technical Bulletin S-06-01, “Introduction to Software Configuration Management,” is available on this website for further detailed guidance surrounding these plans.

Q-5. “What is the purpose of the new Part 236, Subpart H, and what systems does it affect?”

A. The purpose of subpart H is to promote the safe operation of processor-based signal and train control systems that are safety-critical, as defined in section 236.903, through performance-based requirements. Subpart H covers the use of any processor-based signal and train control system that does not meet the exclusions requirements of section 236.911. It is also intended to facilitate the development and proliferation of Positive Train Control systems throughout the industry.