the locomotive braking saga continues

In earlier posts I've described how, about 18 months ago, I took delivery of my first ProtoThrottle and found out that in order to use it, I would have to re-program all 100 of my operating locomotives to activate their braking function(s). After that, it took me a surprising six months to get it accomplished, at the expense of most other progress on the railroad. This post is about how it's been going since then, and what I've learned that caused me to head into yet again re-programming the fleet to improve operations.

Here's the situation the Burrlington Northern finds itself in. When we last discussed this, I had (finally) learned how to adjust the braking rate on Tsunami decoders by setting CV 117 to a value (which is almost impossible to describe how to figure out what it should be) of 169, which gives a braking rate of full speed to zero in about 15 seconds. On the ESU Loksound decoders, I used a LokProgrammer and the PC (not Mac, so I have to run it on a PC emulator on my Mac) software to discover that a setting of CV179=60 provided the same 15 second braking rate as the Tsunami's CV177=169. We adjusted the full speeds to about 50 scale miles per hour, the settings for which varied with each locomotive type.

Momentum matters too, so after some experiments we decided on a coasting deceleration rate of full speed to zero in 54 seconds, which equates to CV4=60 in Tsunami's and CV4=215 in ESU's. This was a deliberate compromise between maximum momentum versus slowing down at a rate that would allow a beginning operator to manage their train even if they forgot about the braking feature.

So, after reprogramming all the locos accordingly, we had a few operating sessions. In general, people seemed to like the braking feature, and felt that it added realism. We standardized on using F9 on all the NCE throttles to activate the brake, and put a "brake" label next to F9 on each throttle, so people seemed to learn it pretty quickly. One problem we found is that the ESU Select and V4 decoders will not brake unless the throttle is turned to zero, whereas the Tsunami's will brake even with the throttle turned up. Once people learned this, it was ok, but this discrepancy between the braking behavior of ESU's and Tsunami's is irritating. The Tsunami's behavior is prototypically correct, and ESU has recently fixed this defect in its new V5 decoders.

Then, I operated a few times on Joe Green's excellent layout in Sequim, WA. He had all his locomotives set to a maximum full speed of 30 scale miles per hour. The effect was great. It made the layout seem larger, the trains seem heavier, and the engine sounds changed more as you increased speed. On my layout I had found that I almost never ran faster than speed step 12 (out of 28), while on his layout I used the full throttle range, depending on the situation.

So, I made the dubious decision to reprogram all the locos again, this time to reduce the max speed to 30 scale miles per hour. Groan. But to make sure, I just reprogrammed one and played with it for a while. You can already guess what I found out. The brake settings no longer made sense at the slower max speed. Taking 15 seconds to slow down from 50 to 0 MPH is one thing, but taking 15 seconds to slow down from 30 to 0 MPH is an eternity. On a model railroad, at least.

After testing a while, I decided that a 10 second max to zero braking rate is just about right. (Ironically, this is the value that ESU puts in their braking rate by default, before I started this whole mess!) So the new CV values are, for Tsunami's CV117=175 and for ESU's CV179=40. Now I'm off to the basement to reprogram the rest of the fleet.

One footnote to all this - I found out from Doug Paasch that in fact some of the QSI decoders also have a programmable braking function. I had taken the QSI's off the layout, but as soon as I figure out how to get them adjusted to a 10 second braking rate (and re-mapped to have F9 trigger the brakes, if possible), I will bring them back on the layout.

A second footnote - to keep things simple I've just set up one function key to control one braking rate. A real locomotive has three types of brakes: train brake, independent brake and (sometimes) dynamic brake. Tsunami has CV's for all three of these, and if there were enough digits between 0 and 9 (an no other functions you cared about) you could have function keys for all of them all on the face of your NCE throttles. But it's complicated enough to get people to use a single brake without bogging down in multiple brake types. I want my layout to be easily accessible for people with varying levels of knowledge about railroads. So I'm just sticking to one brake for now. Who knows what will happen in the future?

A third footnote - I didn't change the CV4 (deceleration) values. I think this will be ok, but it's true that, relatively speaking, the deceleration will now seem slower that it did before. This of course makes the brake more important and more fun! (Another way to look at this is, with 30 as a maximum speed, you won't be in the next town by the time your deceleration finishes, even if you forget to use the brake.)