Passenger Brake Operation

[TonyD]

As afar as interest to models here, which I think is one of the most intellegent threads going this week....OK thee best thread, Redtail mentioned the differences in the braking systems in the 1st gen. diesels, which is why some models and brands couldn't be MU'ed with some others- RS1's could mu with some early Alco switchers, but not with RS-3's or later anythings, btw, as in another thread, it was a few differences in equipment that kept the Baldwin Sharks on the D&H from mu'ing with anything else, which was a real sore point, just something for modelers to keep in mind. As for GG's question, I would think since the Iron range really doesn't interchange the ore cars, and they stay in a unit train until one has to go on a bad track, I guess any system the fed's OK that they think works best is just fine. Speaking of guilf--- A few years ago an old B&M veteran died from a car getting away on the Hoosic tunnel line around Orange or Athol, a money saving two man crew switching on the mainline, and a handbrake on a box just didn't hold, must have looked like a scene from and old movie, the engine trying to catch up with a runaway, I guess when the couplers did hit, at speed, the oldtimer fell of the porch, I wonder if keeping footboards wouldn't have saved the day..who knows...seems he was scared about grade crossings further down hill, a Casey Jones kinda hero, no one ever hears about...on the same line in the strike years, a crew of 'imported professionals' all got out of the cab to buy a nice lunch....when they got back, the train was gone, of course first thought was the strikers, but, apparently it just decided to go down hill without them...to help save Guilford some money, such nice engines! Reminds one of Thomas and freinds

[Redtail67]

Guilford Guy:

I am not familier withe operation of the DMIR. They may have in use a straight air brake system if they are a captive Rail operation. That is one that does not interchange their equipment with other lines.

I simply know of no advantage to a straight air system over the modern day brakes. One for the reason you mentioned, the bleeding down of the brakes to lessen the amount of brake force against the wheels.

It was for that very reason the straight air systems in main line operations were replaced, they were unsafe and unreliable.

Redtail67

[Redtail67]

TonyD:

This failure of locomtives to MU was very common with interchanged units or where we would pick up an old switcher to send off somewhere. It was nothing but a nightmare for operating crews. You would end up setting the unit up Dead In Train to be able to haul it.

Further, among our own roads power, this inability to MU the Units led to a "loss of available horspower for the train". If the units were not setup properly it would result in sliding wheels and sometimes derailment.

When we started interchanging entire trains with units included it really showed up when we added ATSF Units to a forein line consist that had opposite arrangment of the air hoses. This would result in the trainmen or engine crews lining up the hoses straight across as they had been taught and this would sometimes in having the independent application and release hose crossed with the sanders, or actuation lines.

This would flatten the wheels  causing you to have to set the units out or sometimes derailment.

The railroads addressed this and started making all new units built have the same pipe arrangement and they converted all that were feasible of the older units.

Frankly, because this is a modelers forum, I am surprised at your knowledge of the air brake system.

Of course if you are making a model of one of these Steam Air Brake Equipped Locomotives and you want detail that would have to be taken into account. I ran many Alco RS-1and RS-2 units and they all had this early brake on them and were not equipped with an actuating pipe. They would only MU with units of the same type.

Redtail67