>Funny thing is I have spent far more time as an engineer without dynamic brakes and run most trains with air only. I like dynamics and don't have an issue running with them. But the simple fact is every engineer has had and will have a train try to get away from them. Even moving trains of the same size over the same territory, most will behave as expected but some just won't. I've seen too many engineer's that did not have controll of their train, and the dangerous thing is that they did not have the skill/experience/training to realize it.

Dynamics have their place, so does air. The problem is that modern-day management, in its infinite wisdom an sagacity, thinks of dynamics as THE universal braking tool, which they most definitely are not.

>Most commuter and regional passenger operations expect the engineer to operate the train at full performance, accelerating and decelerating to meet the schedule or gain time when running late. WHy do you think they keep increasing the commter locos horsepower? In most cases, it isn't needed to maintain track speed but to accelerate faster.

Amtrak has caught the fuel economy bug too, and believe me, blended braking with a long haul plays havoc with the waiters in the dining car.

>Same thing with dynamics - the engineer's are expected to come roaring into a station and hit their mark - every time - regardless how well the brakes work. If the dynamics fade or drop out, then the engineer has to take quick action to get it stopped/slowed in time. Not the ideal situation, not consistent with many rules/regulations, but what the rules say isn't exactly common practice on the railroad.

I always discourage my students from to grandstanding and showing off but rather always require they give themselves a margin of error (i.e. never use more than a 15 lb set as a matter of course when making slow downs and stops). This way if they overlook something, which is inevitable on occasion because it's part of being human, or something goes haywire, then they would be in a good position to save the day by going deeper than normal. Besides, using full service with blended braking (a 31-32 psi reduction) causes too much passenger discomfort, standees in particular.

>> This is not quite what I've observed in 25+ years of operating psgr engines equipped with blended braking.

>Both NYAB/Knorr and Wabtec/Wabco have issued insturction manuals describing braking systems and including recommended piping arrangements. Most of the 6ET/14EL/6BL and older systems tend to follow these designs, but of the many 26L/NL systems I have worked on --snip-- 49CFR that the railroads have to comply with, after that it is a free for all and at times railroads have very different ideas compared to each other.

Over the years I've collected nearly 200 of these manuals, ranging from plain triples and Schedule A-1 all the way to ABDLX and Knorr's EAB, including vacuum brakes and brake systems manufactured by companies most people have never heard of. Of these, I've read about 1/2. However, I was speaking about the interplay of automatic/dynamic braking effort during blended braking on passenger locomotives, commenting that I never saw locomotive BC pressures above 10 psi at speeds greater than 40 mph on a consistent basis, which is to be expected because no two locomotives behave precisely the same way in the same situation, not to mention that systems wander out of adjustment, solid state ones as well as mechanical.

What we may have forgotten make clear to our readers is that for automated blended braking to occur, the throttle has to be in idle and the independent must not be bailed off when the automatic [train] brake application is made, and that bailing when blended is operating will cancel blended braking altogether until another automatic application is made and the locomotive not bailed. With manual blended braking, you can do just about anything you please, but don't get carried away because it's all to easy to slide the wheels.

Yes, there are two schemes of DB lockout magnet valve configuration. This simplest way to determine which one your engine has (this can be done with the locomotive stationary) is to make an automatic reduction sufficient to produce a higher BC press than your current IND application, don't bail, open the dynamic throttle until you hear BC exhaust, and then close the throttle. If the locomotive's BC pressure returns to the same value caused by your automatic application, you have one scheme, if it doesn't, you have the other. The SP used the first scheme, Amtrak uses the second. This goes way back, far enough to be covered in Drennan's Chalk-talks of the 1950s/1960s.