Just curious... Why do American locos. have notches & British ones don't ( 66 is American built ) ? 37, 40, 45, 47 all have a continuous throttle. Is there a technical reason behind this implementation ? And how their construction & performance compare in this regard ?
I don't know exactly, but it might have something to do with whether the power is applied diesel-hydraulically or diesel-electrically. With the diesel-electric drives alone, a distinction is made between three different systems, which certainly also require different controls. But I don't know more about it.
No, it actually stems from the fact that, from the time of the original FT back in 1937, US diesels were intended for multiple-unit operation. Although it is possible to use variable voltage for a control signal, line attenuation and fluctuations (remember, this was the 1930s) made that a less than reliable option. So instead they decided on 8 possible positions, since three wires can send 000-111, or 0-7 binary, with no risk of error. (It also made control systems for prime movers easier, since they were working with predictable discrete states). The convention has stuck ever since, even though naturally it hasn't actually been necessary for a long time.
REALLY ?? Is it just so the MU cables can send the Octal code without glitching ?! I mean thanks for the reply, but really it's quite a shock that I never heard about this. I always thought it had something to do with the prime-mover's performance and maybe Brits. innovated some workaround. But after reading your comment, I feel like I've been thunderclapped... 23 years of railfanning and it was hiding in plain sight ( maybe you do learn something everyday afterall... ) Anyways, can you please suggest some resources that I can refer to for more insights ? Thanks again !
