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Recommendations, Regulations, and Requirements
IEEE
AREMA
MIL
CENELEC
EN
ANSI
AAR
IEC
ASME
ASTM
...
Automation
industry norms
tend to be quite
stringent
Compliance with
automation norms
does not mean
compliance with
railroad norms
railroad automation is that the European industry has implemented standards and
norms which are followed by both the industrial automation and railroad industries.
This is quite different in the U.S. where the railroad industry has maintained its
independence from manufacturing and processing industries and norms, while
maintaining its own industry-specific criteria, and incorporating specific guidelines
such as IEEE or MIL standards as needed. What complicates this situation even
more is that the U.S. factory automation industry has partially incorporated - or at
least recognizes - the established European norms, leaving U.S. railroaders quite an
isolated bunch.
This myriad world of norms provides a veritable spaghetti of interrelations,
dependencies and abbreviations. Railroaders discuss terms such as AAR, AREMA
(not a Standards-forming organization), and FRA. CENELEC, SIL, EN, IEC are
European contributions, while the U.S. automation industry brings in ANSI, AMSE,
IEEE, and ASTM - did I mention MIL?
Is it possible to make sense of any of this or should railroaders crawl back into their
bungalows and continue to wire up 12V relays and AAR terminals?
Actually the topic is not as complicated as it looks - after you've spent weeks
reading through paper that is. Primarily, the major standards all require
approximately the same basic fundamentals: structured, high quality development
process, quality controlled production, proven mechanisms of hardware and
software, and structured documentation. The automation industry norms tend
to be somewhat more demanding than railroad norms - again probably due to the
industry's size. That is one reason why some railroad -specific norms and best
practices tend to reference them as needed.
For railroaders that generally means that if a product is compliant with automation
industry norms and standards it can be expected to fulfill its stated purpose and
be at least of as high a quality as the railroad-specific products they are using.
Products which comply with CENELEC standards, for example, have been
developed in a tightly controlled and very prescriptive regulatory environment and
tend to have a depth in development, production, and quality process not seen in
products developed specifically for the U.S. rail industry.
Unfortunately that high quality does not mean that they comply with
railroad-specific norms such as AREMA. As a matter of fact you can bet that they
probably don't. Railroad-specific requirements, such as those in AREMA can not
be expected to be found in any other standard because no other industry has the
same interfaces, environments, etc. Unfortunately such railroad-specific
guidelines are sometimes lagging behind modern system designs because they
tend to be focused entirely on a reflection of the existing railroad-specific products.
For example, some of the fixed values prescribed for hardware design
characteristics would cause an automation industry engineer to wonder if he had
time-warped backed to the 80s.
Lessons for Railroaders:
1. Major norms and standards tend to require essentially the same things.
2. Automation industry norms tend to be more comprehensive and detailed than
railroad-specific norms, although they lack the railroad-specific requirements found
in AREMA, FRA, etc which are vital to the railroad industry.
3. In some cases railroad-specific norms are somewhat outdated compared to
automation industry norms.
discussion on
this issue can
be found in the
introductory text
to the new FRA
236 Subpart H
Rule
