Articles

Articles on ballastand crushed stone.

Railway Ballast12 May 2026

What is railway ballast?

Ballast is the crushed stone layer under and around the sleepers. It carries load, holds the track and lets water drain.

Railway Ballast08 May 2026

What makes good railway ballast?

Good ballast is hard, angular, clean and correctly graded. Soft or dirty stone fails under traffic.

Mining28 Apr 2026

What is andesite?

Andesite is the volcanic stone extracted at Nangerd. After crushing it becomes ballast, sand and gravel.

Processing20 Apr 2026

From the face to the wagon

Ballast is made in a fixed sequence: extract, crush, screen, inspect, load. Skipping a step shows in the pile.

Railway Ballast14 Apr 2026

Ballast and sub-ballast

Ballast and sub-ballast are different layers. One is coarse and open. The other is finer and sits below it.

Aggregates06 Apr 2026

Why grading matters

Grading is the share of each size in the pile. It decides drainage, strength and how the stone is used.

Aggregates30 Mar 2026

What is crushed sand?

Crushed sand is stone broken below 4 mm. At Nangerd it comes from the same andesite as the ballast.

Infrastructure22 Mar 2026

Stone in railway work

A railway is steel on timber or concrete, sitting on stone. The stone decides how long the geometry lasts.

Technical Knowledge14 Mar 2026

Fouling and drainage

Clean ballast drains. Fouled ballast holds water. Water under the sleeper is the start of geometry loss.

Technical Knowledge06 Mar 2026

Particle shape and tamping

Angular crushed faces lock. Flat or long particles break under the tamper and make new fines.

Technical Knowledge26 Feb 2026

Frost and water absorption

Stone that takes up water can break in frost. Absorption limits exist for that reason.

Processing18 Feb 2026

Quality control at the plant

A named standard is a promise. The plant has to check the pile against that promise before loading.

Infrastructure10 Feb 2026

A quarry beside the railway

Ballast is heavy. A plant opposite the station cuts road-haul and can load wagons on the same site.

Andesite & Stone20 May 2026

What is rubble stone (sang-e lashe)?

Rubble stone is sound extracted stone that is not used as dimension or facing stone, but is strong enough for riprap, walls and foundations and as feed for ballast, aggregate and stone powder.