Auxiliary water tenders

[Gumboots]

Here's something that popped up in a morning browse: Page 47 - Auxiliary water tenders

These were used IRL in quite a few places and would be very easy to make. All you'd do is set the first tender to be ****T_Truck1 and the second to be ****T_Truck2. Piece of cake. Given that they could share the majority of their skinning, it should be easy to fit both on the one image.

I can even see a use for them in a scenario. You could have two variants of the same unit: one with standard tenders and one with auxiliaries. Have an event that allows you to choose the upgrade. If you take it, the event halves water usage and makes the new (more expensive) units available while simultaneously making the old ones unavailable. Since an auxiliary water tender would cost far less than a standard loco+tender combo IRL, I am guessing the price rise would only be of the order of 10-20%.

Edit: Just looking into it a bit more and found this - https://en.wikipedia.org/wiki/South_Afr ... ter_tender

The short version is that several classes of South African Garratts (Class GM, Class GMA, and Class GO) were specifically designed to run with auxiliary tenders, and with the locomotive itself carrying no water at all. This is obviously unusual for a Garratt, but was adopted by SAR to reduce axle loading on some of their lines. Apparently it worked very well.

So that means that anyone modelling those classes should really figure out a way to have 6,800 gallon* auxiliary tenders with giant Garratts. Which sounds like ridiculously good fun.

*These were Imperial gallons, not US gallons. In US terms it'd be about 8,200 gallons. In metric it's 31,000 litres.

[RulerofRails]

South Africa also had Condensing tenders. Those are interesting too. I remember reading about water scoop systems (fill without stopping) in use somewhere in Britain (IIRC).

On the wiki page for the GMA/M Garratts we find this:

Although the SAR specifications called for a 15 long tons 14 hundredweight (15,950 kilograms) maximum axle loading, the Class GMAM spent its entire career running on track that could take 18 long tons (18,290 kilograms) or more. Without the restriction of the coal bunker and onboard water tank capacity to 14 long tons (14,220 kilograms) and 2,100 imperial gallons (9,500 litres) respectively and the necessity to haul along a water tender, the class would have been much more useful and their service lives could possibly have been prolonged. Their shortcomings as traffic machines was possibly one of the root causes of the rapid mainline dieselisation of the SAR in the 1960s.[15]

Here the necessity to haul along a water tender is portrayed in a negative light. Although, maybe it's just someone griping about a fault the way we do with RT3. The source is from a site called Soul of a Railway (homepage linked). Lots of pics of Garratts etc. there.

[Gumboots]

S'pose it depends on whether you think the axle loading is important or not. For some reason the people running the system thought it was.

And yes I knew about the condensing tenders and they are an interesting piece of kit. Apparently they not only gave massive range (the same water could be re-used up to 8 or 10 times) but they also gave a reduction in fuel costs because the condensed water was still quite hot, which effectively acted as an automatic feedwater heater when sending it back to be used again. Which makes you wonder why they weren't more widely used if they were that good.

And the Poms used scoops quite a lot for express services. They were used in the US to some extent too, but I don't think quite as much (could be wrong about that).

[LV628]

I would say, if there is a way to modify water consumption by locomotive and not event, I would have but auxiliary and non-aux versions available so you have the option to use an aux version from say New York to Chicago versus the non-aux version for much more local service.

[Gumboots]

No way of doing that. The editor only allows a game-wide event.

[LV628]

I mean in the .lco files, edit fuel consumption between each version. I haven't dug into that code yet, so I'm shooting in the dark hoping I hit something xD

[RulerofRails]

I assume a typo and you meant water consumption. You can try. I wish it was there, there are a couple of unidentified/unknown variables in Pjay's notes #'s 3-6 (#1 is now called "Free Weight", and #2 is Pulling Power), but from my observations of their use it seems unlikely that they have anything to do with water consumption. But, never say never.

Pjays notes are very helpful with the file types. Now that the files are on Mediafire, I wonder if it's a good idea for direct links:
RT3 Notes that point to the file on Mediafire?

Otherwise, find "RT3 Notes" on this page. Or maybe you already downloaded them.

[Gumboots]

You can certainly edit fuel consumption in the .lco files, but that won't have any effect on locomotive range when playing. All it will do is change your fuel bill. However, if you were thinking that a decreased fuel bill would be good for the high mileage trains then sure, you can have that. The only catch is that the same reduction could also make them the better choice for short hauls.

If you wanted to balance things so that the extra purchase cost of the long distance units only paid off in reduced fuel cost over long distances, while still having the other units be more economical over shorter hauls, then that may be possible but would require some testing to get it right, because predicting what mileage they will cover per year is difficult without actual game data.

Anyway the contents of the .lco files are well-known now.

00 : 4 : D507 0000 : File header
04 : 30 : String : loco short name / unique id
34 : 4 : float : top speed
38 : 4 : float : free weight
42 : 4 : float : pulling power
46 : 4 : float : ?3 (all = 0.5, except E60CP=0.0)
50 : 1 : int (diesel+electric+fairly+shay=255, others=?) 255 must mean no tender.
51 : 4 : int : acceleration
55 : 4 : int : passenger appeal
59 : 4 : int : reliability
63 : 4 : float : cost
67 : 4 : int : fuel type
71 : 4 : float : fuel economy
75 : 4 : float : annual maintenance
79 : 1 : byte : US availabillity
80 : 1 : byte : EU availabillity
81 : 1 : byte : WORLD availabillity
82 : 1 : byte : padding : 00 or CD
83 : 4 : int : locomotive sound
87 : 4 : int : whistle sound

Of that lot, the only ones worth playing around with might be 46-49 inclusive, and 50.

My best guess is the 46-49 do nothing, since the only loco which isn't set to 0.5 there is the E60 and there appears to be no reason to think there's anything different about that one.

We know a value of FF (255) for byte 50 means no tender. The Shay and Fairlie and others have FF there, but default locos that have tenders have a range of values that AFAIK have never had much (if any) testing. The Red Devil is 25 (37 in decimal) while the S3 is 27 (39 decimal) and the Stirling is 2F (47). Now these might be meaningful, or they might not. We know there is deprecated code in RT3, so it's possible that these other values were meaningful during alpha but are not meaningful in the final release. You'd have to test carefully and be on the lookout for confirmation bias.

[Gumboots]

Just as a quick bit of misbehaving, since I've been behaving myself lately, here's a proof of concept done on Tomix's UP skin for the Big Boy. Uses the same tender image as the default tender, just with minor adjustments to mapping, and is pretty close to the real thing. The same would also work for the Challenger since they use the same tender anyway. Other locos should also be pretty easy.