Dominic Mazoch posted:1472? Why that and not 1500 days?
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> How did the FRA / Congress come up with 1472 "fire
> days" for a boiler and tubes? Why not 1471? Why
> not 1500? Seems like an odd number to me.
The number was actually set by the steam operators advising the FRA (people like Steve Lee and Linn Moedinger, among others).
It's essentially four years of daily service, similar to previous boiler regs. Generally speaking, when steam locomotives were used in regular service, railroads based maintenance cycles on miles, not months, and maintenance standards exceeded the ICC regs. It would have been unusual for a locomotive on a Class One to go 48 months (the maximum interval the ICC allowed between boiler inspections) without a flue replacement.
The thought process behind the 1999 rules is thoroughly documented in the original PDF of the rules:
http://www.steamcentral.com/documents/49cfr230.pdf
The rules were driven by those working in the industry, who actually pushed the FRA to adopt them.
3. 31 and 92 Service Day Inspections This rule also establishes 31 and 92 service day inspection requirements. These are roughly comparable to the monthly and trimonthly inspections in the 1978 standards.
92 'quarterly' service days * 16 'quarterly' inspection periods = 1472 service days. The '1978 standards' are essentially the rules from the steam era, with a few tweaks.
4. Annual Inspections In addition, this rule establishes annual inspection requirements similar to the 1978 standards: requiring that a steam locomotive be inspected after 368 calendar days have elapsed since the time of the prior annual inspection. The 1978 standards required that certain items be inspected at least ‘‘once every 12 months.’’ The revised annual inspection, as do all the other periodic inspections, incorporates the inspection requirements of those inspections required to be conducted more frequently. Thus, locomotives that are not operated often enough to accrue either 31 or 92 service days in a 368 day period will have those inspections conducted, at a minimum, once every 368 calendar days. 5. 1472 Service Day Inspection Finally, the 1978 standards required that a steam locomotive boiler be inspected, at a minimum, once each 5 calendar years (boiler interior to be inspected after 48 calendar months, within 5 consecutive years; and the boiler exterior to be inspected every 5 years, or, if the locomotive is out of service for at least one full month during that time, after 60 calendar months within 6 consecutive years). This inspection was a major one, requiring the removal of the jacket and lagging to conduct the exterior inspection, and the removal of all flues in the locomotive boiler to conduct a ‘‘minute’’ inspection of the interior of the boiler.
