For the full readme guide, see the download for SPI 1.2.

Changelist for 1.3
==================

A new game is required as this uses a different GRFid.
Farm supplies return, giving a small boost to farm based industries.
   Supplies can stockpile but are used slowly, 9 per month or 18 per month if the stockpile hits 200.
Add fertiliser plant, making farm supplies.
Machine shop now makes farm supplies as well as building materials.
Engineering supplies also make a comeback. They operate in the same way as farm supplies but for mines.
   Note that if mines have reserves on, supplying them with engineering supplies will just make them extract the
   fixed amount of reserves a bit quicker than normal.
Smithy Forge and Machine shop change to make FMSP and ENSP.
Lumber Yard now makes building materials and ENSP.
Add synergy feature. Industries with 2 or 3 raw materials can get production boosts if 2 or 3 materials are stockpiled
   to at least 250 units.
   So, a brewery with 300 grain and 40 supplies will do 2 runs (using 10 of each). If there were >250 supplies then there
   would be 4 runs, 2 using grain and 2 using supplies.
   This encourages a player to actively ensure that an industry has a good supply of raw materials to get lots of extra
   production runs. If a brewery had lots of grain then adding supplies would allow faster production than just grain.

Lumber yard is now service-aware. No idea why it wasn't before.
Smithy forge added to service-aware.
Petrol removed as a cargo.
   Oil refinery now makes just chemicals. Machine shop accepts chemicals instead.
   Petrol pump accepts just food and goods. This needs changing eventually.
   Bulk terminal accepts goods instead of petrol. Port now provides farm and engineering supplies.
   Now 4 sources of engineering supplies and 5 for farm supplies. 
Oil refinery now makes 1 product so doesn't need to be service-aware.
Cannery should now be placed further away from fruit sources (and vice versa).
Service aware limits tweaked to allow up to 95% of products to be a favoured type.
Woodlands now get a smaller reserve value so they can be cleared more quickly, lasting approx 20-30 years.
   They also get a higher production rate so they will clear more quickly.
   They don't accept or need engineering supplies.
New production system to allow multiple runs per cycle if stocks are sufficient.
   Also allows secondary raw materials to have multiple runs if the main raw material has at least 20 in stock,
   so a brewery can use extra supplies provided there's grain available. Without grain, supplies are limited to
   one run per cycle. Ditto for other industries.
   Some multi-input industries have differing production bands for secondary inputs.
   Steel mill, iron ore gets a second run at 500, coal at 800 and scrap metal at 1000 stocks.
   Iron ore gets a third run at 1000 (as long as there's 20 coal or scrap metal available).
   All industries get extra runs when a stockpile reaches 8000 or a multiple, this acts as a dampener on stockpiles.
   Secondary production levels can increase massively with a good flow of raw materials.



SPI 1.3 new features
====================

This is being released way before I intended due to the situation that I will lose internet access for an unknown period of time...I'll be back once I get my internet sorted out but that's low priority for now.


Engineering and Farm supplies.
==============================

While they were the first thing I disabled when starting my own version of the FIRS code, I've now added them back into the game. They are handled completely differently than how they operate in FIRS.

Supplies are stockpiled and are used at the rate of 1 per cycle (up to 9 cycles per month). They give a boost of 2 extra products (or 1 each if the industry makes 2 products).

A cereal farm might be producing 8t grain per cycle to a total of 72t in the month. With 1 unit of farm supplies used each cycle, that increases production to 10t per cycle, 90t in a month, a gain of 25%. 

If the farm supply stockpile is over 200 units, then the farm can use 2 supplies per cycle. That would make 12t per cycle and 108t per month for a 50% boost over normal production.

An arable farm (for example) gains 1t for each of grain and fibres per 1 farm supply used.

Engineering supplies work exactly the same way but for most extractive industries. With just 1 product, 1 engineering supply will increase output for that cycle by 2t of the product.

Note: If reserves are on, engineering supplies will simply have the effect of exhausting the mine at a quicker rate, so the effect will be less pronounced than for farm supplies.

If bankruptcies or mine reserves are on, it's possible that large stockpiles of engineering/farm supplies may be lost if the mine/farm closes...so beware.

I know they do not provide massive increases as happens in FIRS but I feel their effect here is proportional.


Production system and synergy
=============================

The rigid original system required a steel mill to have enough iron ore, coal and scrap metal to produce metal. Not enough of one material and it did nothing or almost nothing. That made it extremely difficult to get production going. 

Using the alternative production system means that a steel mill can produce metal with just coal. While not ideal (or realistic) it does make for a more fluid game.

Using the half-alt production system: (My favoured choice of production system)

Industries use 10t of raw materials to make 8t of product. There are various bands than allow extra production runs each cycle. So, a steel mill gets a run at 20, 500, 1000 and every 8000 of raw material stockpiled. (subject to further change)

That means even if just iron ore is supplied, the steel mill will make metal. At a 8000t stockpile it'll perform 4 runs per cycle (40t -> 32t metal) for 288t per month. If you were able to add 8000t of coal, that would also make 288t/month. Adding 5000t of scrap metal would also have the same effect. At this level, production could be as high as 864t/month.

However, each raw material acts independantly. 8000 iron ore, 300 coal and no scrap metal would make 4+1+0 production runs with 40t iron ore and 10t coal used to make 40t of metal.

But now there's also synergy, a bonus for when 2 or more of the required raw materials are in stock at a level of at least 250t. 

So in the above example: 
8000 iron ore, 300 coal and no scrap metal would make 4+1+0 production runs with 40t iron ore and 10t coal used to make 40t of metal.
There would also be an extra run for iron ore and coal as both are over 250t in stock...making 5+2+0 runs, turning 50t iron ore and 20t of coal into 56t of metal.

If there was also 250t of scrap metal in stock then it would be (4+1+1 and 2+1+1 = 6+2+2), 10 runs to make 80t of metal. That's because you get 1 extra run for iron ore+coal and 1 for iron ore+scrap metal, so 2 extra runs for each raw material. Industries having 3 inputs can generate a lot of extra production if you can keep them well stocked. As iron ore is the critical component, there's no synergy bonus for coal+scrap metal regardless of how much iron ore is in stock.

Finally, as a way of tackling problems with the stockpile limit, every 8000t of stockpile will generate extra production runs, so were you able to accumulate 64000t of iron ore, that amount would generate 11 production runs in total for the iron ore (20/500/1000 and every 8000) reducing the stockpile by 110 tons per cycle. I suspect that only in exceptional circumstances would you be able to get that much iron ore stockpiled...I have managed to get 47k wood stockpiled at a paper mill by taking all the on-map wood there.

Smaller industries have different bands of extra production, and for places that have a main ingredient and a secondary one, the main ingredient can earn extra runs but the lesser input can't.

A brewery inputs grain and supplies. Grain gets production runs at 20/500/1000/8000+, supplies gets 20/8000+. A synergy bonus triggers if both have stockpiles of 250 or more. This means that grain is much more important in generating production. 1000 grain and 300 supplies makes 4+2 runs, 300 grain and 1000 supplies makes 2+2 runs (including the synergy bonus).

1000 grain on its own makes 3 runs. 1000 supplies on its own makes 1 run.


-------------

Multiple runs.

The brewery (for example) can do grain runs at 20/500/1000/2500 and 8k+. Supply runs at 20/1000/8k+

It should be possible to tie in the existance of the 'other' input to allow a higher run to be conducted.

Grain can run at 20/500/8k+ without any need for supplies. Booster runs at 1000/2500 need there to be at least 1 supply in stock (even though it isn't used).

Supplies run at 20/8k+ but need at least 1 grain in stock to allow the 1000 run.

That ties input stocks together a bit when trying to do the higher runs so dumping 7000 supplies at a brewery with no grain will just cause 1 run per cycle. Likewise, grain can do 2 runs but then needs some supplies in stock to be allowed the higher runs.

A steel mill works similarly, the higher runs for iron ore need at least 1t of coal or scrap metal. For coal or scrap metal, their higher run needs at least 1t of iron ore. If there's just coal then it'll do runs at 20/800/8k+...it needs iron ore in stock to perform the 1500 run.

Large industries have up to 4 runs on the main ingredient. Small industries have just 3 runs. Secondary inputs have 1 or 2 runs. The 8k multiple levels kick in regardless as they are safety valves for stockpile limits.

A steelmill with 2500 of each input can do 16 runs in a cycle, 4+3+3+4 synergy...for 1008t per month! using 60t iron ore and 50t coal, 50t scrap metal per cycle...540t iron ore and 450t coal and scrap metal. Keeping all that supplied would be quite a feat.

Each subsequent level is approx 2* the previous level.

I may get around to listing the variuos production levels for each industry.

