Tackling The Wrong Problem

I recently ran into this interesting post.


My first thought was, interesting.  My second thought was that the shop forces must have LOVED this.  The fact that the locomotive only logged 70,000 km in six years is telling. What the locomotive saved in coal, it more than gave back in extra time in the shops.

Porta was one of the of those engineers trying to save the steam locomotive by taking all the tricks and making the engine more efficient.  The problem is that chasing higher thermal efficiency is looking at the wrong problem in railroad locomotives.  The issue with a railroad locomotive is reliability and availability.  The higher a locomotive’s availability and the less time it spends in the shop, the more money it can make.  That’s why the Diesel locomotive replaced steam so fast.  Once the Diesel technology had evolved enough, the steam locomotive was not even in the same ball park.  The amount of work required at the shop diminished incredibly and what work was required didn’t require that the locomotive be torn down to the frame and have the boiler deriveted and put back together occasionally.  All the added superheating, compounding, stack efficiencies and all the other thermodynamic tricks only make the shops crew’s jobs even harder. Which is why Argentina only logged 70,000 k and probably spent far more time in the shop than it did running.  With that big shroud, pulling the flues must have been a nightmare. to say nothing of clearing out both stacks before doing that.  Inside cylinders and the related valve gear have always been a maintenance headache.

Even a typical locomotive required a ton of work to keep it running.  Adding things like compounding, special valves and superheaters only makes the job far more complicated. Consider this video and the amount of work involved.

In even the worst diesel locomotive none of that applies.  In addition, there’s no track pounding, no driver wear and no rods.  The entire bogie can be pulled as a unit and repaired with a small crane.  Even in a large shop the work doesn’t require the levels of teardown that a steam locomotive does.

Reliability and availability is the keyword where you are delivering a service.  Going down because of equipment failure when lives may depend on it is not an option.  That’s true for airlines, railroads or power companies.  Somehow, the political meddlers don’t understand that.  They keep advocating things that don’t work.  In this case it was one locomotive on a small railroad.  But we have created cronyism and enacted subsidies for unreliable energy and that’s going to have grave consequences at some point if we do not watch out.





  1. MadRocketSci · July 30, 2015

    Somehow, the political meddlers don’t understand that. They keep advocating things that don’t work.

    “Who is John Galt?” ?


  2. MadRocketSci · July 30, 2015

    In aircraft engines, where efficiency is generally a pretty big deal, they’ve done a pretty good job of pressing up against that limit. The things that are done now are to limit CO and NOx emissions, but they lead to complicated combustors that aren’t nearly as stable as a more rich burning combustor. Those are technical problems though, with technical solutions and cost tradeoffs.

    On the meddling end though, I was at a conference where certain of these aircraft engine manufacturers try to one-up each other by designing a more efficient engine, then getting the government to mandate that level of efficiency to de-facto outlaw their competitor’s engines and force everyone into buying theirs. One company was bragging about a move of this sort for a very large diameter ultra-high-bypass turbofan (which is a neat concept technically) but … their engines don’t fit under region-jets, who are now up a creek because the engines they were using are now illegal.


    • jccarlton · July 30, 2015

      Why do I see ridiculous looking high wing regional aircraft with huge honking engines in the near future? The ground crews will just love them.


  3. Pingback: Has Technology Stuck? | The Arts Mechanical

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