Plasser & Theurer MFS 100

Updated: August 2026 – Anyone who sees a long row of identical wagons with conveyor belts on the roof standing in a construction siding is looking at an MFS chain. These material conveying and silo units are the track worksite’s logistics: they bring ballast in, take spoil away, and thereby solve a problem that would otherwise cost hundreds of lorry runs. This page explains the principle and how to recognise them.

What is the Plasser & Theurer MFS 100?

The MFS 100 is a material conveying and silo unit: a specialist wagon that takes in bulk material, stores it temporarily and releases it again via conveyor belts. A longitudinal conveyor belt runs the full length of the wagon above the silo, with a swivelling, height-adjustable transfer belt sitting at one end.

The number in the type name distinguishes size and design classes within the manufacturer’s machine family – it is not a class number in the railway sense. What uniquely identifies a single unit is its twelve-digit vehicle number, which for auxiliary vehicles begins with the type code 99.

The principle: material travels through the whole train

The real trick of these wagons isn’t the silo, but the chain. Taken on its own, an MFS unit is just a wagon with a conveyor belt. It only fulfils its purpose as part of a formation.

Who MFS units work with

MFS wagons are pure service providers. They turn up wherever a machine moves large quantities of material – which happens more often in track construction than you might think.

Task	What the MFS chain handles	Why it’s indispensable
Ballast cleaning	Removing screening spoil, supplying replacement ballast	The spoil is produced continuously and can’t be left lying
Track reconstruction	Removing old material, supplying new ballast	The machine works in a continuous pass and can’t wait
Formation improvement	Removing spoil, supplying building materials	Large volumes, no access for road vehicles
Ballast top-up	Targeted discharge of ballast onto the track	Metered delivery instead of dumping at one spot
Points worksites	Material supply in tight spaces	Short possession windows force fast turnover

The typical partner machine is a ballast cleaning machine such as the Plasser & Theurer RM 95-800 W / RM 80-UHR. For complete track renewals, MFS chains run alongside reconstruction trains such as the Matisa P95 / P100. Localised lifting work, on the other hand, is handled by other vehicles, such as the railway slewing crane Kirow KRC 810 / 1200 – which moves loads, not bulk material.

Numbers, markings, and why a chain pays off

Each unit of an MFS chain is an independent vehicle with its own twelve-digit vehicle number. Its first two digits are the UIC type code; for auxiliary vehicles that’s 99. The keeper country’s country code follows, then the vehicle-specific part, and right at the end the self-check digit.

For observers, that makes MFS chains unusually attractive. Where a tamping machine gives you a single number, here you have ten or more vehicles side by side – each with its own number, often with different build years, designs and keepers within the same train. Anyone who works systematically through the formation from a bridge can log more documentable vehicles in a few minutes than during a whole spotting session on a platform.

Two things are worth noting down alongside that: the keeper’s data panel, because track construction vehicles frequently belong to construction firms such as SPITZKE SE and hire companies and change owner, and the date, because the make-up of a work train changes from job to job. The same machine can be out with entirely different wagons on its next project.

Where you’ll realistically find MFS chains

Unlike working track machines, which you almost only see at night on a possessed track, MFS chains are comparatively rewarding for observers. They often stand stabled for days ahead of and after a construction project – in construction sidings, at connecting lines, in station approach areas and shunting yards.

That makes them one of the few engineering vehicles you can realistically plan to find. Shunting and stabling areas are the most productive place for this; which locations are suitable and publicly accessible is covered in the guide to spotting at a marshalling yard. Because every unit carries its own number, a well-kept logbook really pays off here – how to set one up is shown in the article on keeping a sighting logbook.

What distances apply here and why they aren’t negotiable is summarised in the article on safe distance at the track.

Common mix-ups

Verdict

The MFS 100 isn’t a spectacular vehicle, but an indispensable one. Without material conveying and silo units, every larger track worksite would choke on its own logistics. For observers, the wagons are doubly interesting: as a collecting field in its own right with plenty of individual numbers, and as a reliable sign that construction is happening nearby – often before it’s been announced anywhere.