ModelSave_motorway_edition

ModelSave_motorway_edition is the Motorway-pack version of ComfyUI's built-in ModelSave: it writes a model to disk as a safetensors file, but instead of taking the model on a wire, it reads it out of the MOTORWAY 🚌💨 bus by key.

The native node is the end of a model-merging or training pipeline - the step where you finally commit a merged or modified checkpoint to output/diffusion_models. You give it a filename_prefix (default diffusion_models/ComfyUI, which becomes ComfyUI.safetensors in your output folder) and it saves whatever model it receives. That's it. There's nothing generative about it; it's a save button for models.

What the motorway edition changes

Like every _motorway_edition node, it's a generated clone from clone_nodes_in_the_dangerzone/nodes.py. The interface: MOTORWAY 🚌💨 in (required), the filename_prefix widget, and one key string:

• INPUT_model_key (default model) - bus key holding the model to save.

It pulls the model off the bus, saves it to disk, and outputs the cloned bus - so it can sit in the middle of a graph without breaking the ride. Unusually for this family, there's no OUTPUT_*_key here, because ModelSave has no model output to write back; the only output is the bus itself. It's the "output node" of the merging flow, bus-flavored.

Installing

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

or ComfyUI Manager → "ComfyUI_agilly1989_motorway", then restart. No pip deps, no model downloads.

The fragility you should know about

Read this before you build a merge workflow on this node, because the pack's own README flags it: the update notes say the _motorway_edition clones that won't work are the ones with custom JS and output nodes. ModelSave is an output node in spirit, so it's precisely in the "may not work" bucket the author calls out.

Beyond that, the family's usual caveats apply: the clones are auto-generated at import time over every registered node, and that's how a 2025 user hit a startup crash - an unrelated RandomModelClipVae class lacking a CATEGORY attribute took down the whole Motorway import. The 1.1.7 hotfix then disabled the clone loader entirely, so on current versions this node may not appear in your menu at all.

Practical take: for saving models, the native ModelSave is one wire away and far more trustworthy. Reach for this edition only if your entire merge pipeline lives on the bus - and even then, verify the file actually lands before you trust it. A failed save is a silent data-loss event, and this is the sketchiest node in an already-sketchy family.