Hello, I need help understading some basic info about SD40 - especially the one on Clinchfield DLC. Need your knowledge and expertise 1. Cut - off valve a. OFF - i understand that b .FRT (Freight) - What's the difference between Freight and Passenger? c. PASS (Passenger) - When to use it? And why? 2. MU-2 valve a. LEAD or DEAD - What does it mean and when to use? b. Trail 6 or 26* - What does it mean and when to use? c. Trail 24 - What does it mean and when to use? 3. Selector lever - now this one is a pain a. B - this is for use for dynamic braking, right? Just put it in B and add throttle and it will brake. b. OFF - When to use it? c. 1 - for applying power. d. 2,3,4 - Why and when? Thank you guys!
1. Is a valve that cut-offs the brake control system from/to the train. Freight/Passengers controls the timing of the pressure changes. You apply brakes by lowering the pressure in the brake pipes, but this pressure change takes some time to propagat through the whole train (TSW simulates this). If you have big difference in brake pipe, that means that different portion of the train are having brakes set to different level. This puts stress on the couplers. If you have it in freight, then the locomotive will drop the pressure more slowly when you move the brake handle to apply, lowering the pressure differnce between front and end of the train. You can switch it to passenger when you have a shorter train, the result will be the brakes in wagons will apply more swiftly. 2. This is related to locomotive/independent brakes (which is a separate loop from the main brake). Lead or Dead means that the locomotive brake handle, in that loco, controls the brakes. The rest are setting when you want the locomotive brake to be controlled from a connected cab, and it is the type of valve the lead loco uses for regulating brakes. In TSW it is always always Trail 6 or 26 3. Afaik this defines how the engines are wired to the generator (i.e. parallel vs series). One wiring type maximizes power, while have limited max speed... while the other might offer bigger speeds, but at lower power.... As you drive, the locomotive needs to change between these "wirings", this is called transition (you can notice it by the amp meter droping for a short time). In early diesel-electric locos you had to manualy do this... in the F7, or the SD40 the loco does this automatically for you at certain speeds, that's why you need to only set it to '1'. You can disable automatic phase change, atleast in the F7, and the you would need to switch to different phase manually as you accelerate. Tbh... information like these is what I really miss in the TSW manuals, as it would be great addition for people who like to learn more about how locos operates.
Maybe not. This is true in SPG, OSD and with the UP GP38, but the F7 had 24RL brakes and thus Trail 24 might be necessary in some Clinchfield lashups.
The cut off valve relates to the air brakes, so when it’s in freight, the brakes don’t respond as quick as in the passenger setting. This is due to passenger cars having a release PSI of 110, meaning that the brakes release at that level, while in a freight car the brakes release at 90. This is because passenger trains need to apply the brakes as quickly as possible, for obvious reasons. So when you’re pulling freight cars, the freight setting is used, and when you’re pulling passenger cars, you use the passenger setting. Cutout is when you don’t want the brakes to be applied or released, even if you move the brake handle. The MU-2A valve regulates the independent brakes on locomotives. Independent brakes are the loco brakes, so air pressure does not reach the rail cars, it only affects the brakes on the locomotives coupled to your consist, hence “independent.” Anyways, setting it to LEAD OR DEAD means the lead loco controls the independent brakes, TRAIL 6 OR 26 means the loco does not control the brakes, and just responds to the air pressure coming from the lead loco, and TRAIL 24, I think, is used when the locomotive is “dead in tow” meaning that it just acts like having another freight car in between the lash up, it neither controls nor responds, correct me if I’m wrong. The selector lever determines what the throttle is doing, as far as I know. Setting it to 1 means the throttle is doing its main purpose, applying power. Setting it to the B setting means the throttle now controls the dynamic brakes and doesn’t apply power, and OFF means the locomotive cannot apply power, and is used when the locomotive is parked. You don’t need to worry about the 2, 3, and 4 settings on this lever, those are used to control the transitions on older locomotives, but the ones included in the clinchfield railroad dlc are all equipped with automatic transitions. You only need to understand 1, B, and OFF. Hope this helps.
Yes setting the transition lever to 3 resulted in a spectacular rollback on the 1.5% start up the grade, when I applied power. Oops...
Matt also said in his stream there's no need to worry about settings 2,3 and 4, but I ran one of the SD40 scenarios last night (one where you have 5 units at the front) and it tells you to select setting 4...
When you need massive tractive force, the shunt position is like shifting down into low gear. I found it useful in the Limited Power scenario.
Well, Type 24RL and 26L are two different brake systems. 26L is auto-lapped, and it's the one which has been used by every American loco released in TSW before Clinchfield.. 24RL is a manually-lapped system. The two trail settings are used depending on how the controlling lead is equipped, so that the trails respond to its commands correctly. (Type 6 was already an antique by the time of Clinchfield, really a legacy steam era system, but just might be found on some very old locomotives of pre-war date if they were still around) Note that the MU2A valve only controls the independent (loco) brake, not the train (automatic) brake. If I am reading the tea leaves correctly, the F7's independent brake is auto-lapped and therefore a Type 26. But I might be wrong.
Thank you guys for replies, high quality feedback. Everything is much clearer now Now with basic info clear, time for exploration and experiments. Btw, i just found out that SD40 from clinchfield is also available at sand patch grade for timetables. Nice! I kinda like it more that SD40-2, it feels much more "raw".
No problem, happy to help Just wait till they give us the RS3L horn, then it’ll be a replacement for the CSX SD40-2
For those who may be interested, I've attached an operators manual for the sd40. I have been impressed with how "most" of what is in the actual manual applies to the sim. cheers
