Tekkit 2 Railcraft incompatible with SpongeForge 1.12.2

[Pulz-TCP]

Version

2838-7.4.7, 7.4.8-RC4142

Operating System

Linux (5.10.0-9-amd64/amd64)

Java Version

1.8.0_312/64-bit

Plugins/Mods

https://www.technicpack.net/modpack/tekkit-2.1935271/mods
I'd list plugins I use in production, but I can replicate this with just SpongeForge on its own.

Describe the bug

I'm reposting Railcraft/Railcraft#2089 as I've had no response from that end, so hoping that perhaps we can figure something out from this end?

Description of the Bug
Hosting server for the Technic Tekkit 2 modpack.
Forge-1.12.2-14.23.5.2860
With SpongeForge (SF) present, there are a few combinations of mostly negative results with Railcraft.
Tekkit 2 is also using a version of 12.1.0-beta-8 from Speiger, which I believe is just Railcraft/Railcraft#2086 but cannot be sure. I mention this in case this gets merged.

In 12.0.0, everything worked perfectly.
In 12.1.0-beta-8, with both tested version of SF, railcraft did not work or at worst did not work and caused heavy TPS loss
In 12.1.0-beta-8-Speiger (made for Tekkit 2, v1.1.3), with recommend SF railcraft works but has a heavy TPS impact (a single iron tank can drop TPS from 20 to 16). With the latest SF railcraft does not work and also causes heavy TPS loss.

With SpongeForge 2838-7.4.7 (recommended) present:

Railcraft Version	Does mod work?	Negative performance impact?
railcraft-12.0.0	YES	no
railcraft-12.1.0-beta-8	NO	no
railcraft-12.1.0-beta-8-technic2	some	YES
For example, railcraft-12.1.0-beta-8-technic2 on this build of SpongeForge has issues with the likes of multiblock structures not completing.

With SpongeForge 2838-7.4.8-RC4142 (latest) present:

Railcraft Version	Does mod work?	Negative performance impact?
railcraft-12.0.0	YES	no
railcraft-12.1.0-beta-8	NO	YES
railcraft-12.1.0-beta-8-technic2	NO	YES

Logs
There is no unusual content printed to the logs - only warnings regarding the server running behind in those instances where I've specified heavy performance impact.

I did however do a 5 minute timings report with Spark. The context here is that my server TPS was at 3. Destroying perhaps 7 iron tanks by removing a block brought TPS back up to 20. I did one timing report before and after placing the final block in those tanks. I have also encountered the same performance drop with Blast Furnaces and tanks at other locations and times, just whatever happens to be loaded by a player at the time.

• Forge-1.12.2-14.23.5.2860
• SpongeForge 2838-7.4.7
• In 12.1.0-beta-8-Speiger (works but causes heavy TPS loss)

1. https://spark.lucko.me/5mYwHDzUGu (TPS normal, tanks not finished)
2. https://spark.lucko.me/4NgodjGhtu (TPS down to 5, tanks finished)

I do also have some in-game footage, for whatever it's worth:

• https://streamable.com/us7o4b - Disabling one tank brings TPS from 11 to 20
• https://streamable.com/1pi0mq - After the previous video, enabling 7 tanks brought TPS from 20 to 5, this continued to lower to 3

I would have loved to have tested each of the beta's between 12.0.0 and beta 8 but sadly do not have the time beyond this report!

I'm not sure how much further I can help but feel free to ask; thanks for looking at this report.

Link to logs

No response