Dear Nathalie, if you would be so kind to post some CONTEXT and CLARIFICATION to the question, you would receieve answers sooner and easier, not forcing the answerer to do an endeless search on the internet. If I would not be a railway fan, I would never know that your answer is about the railway! (dormentes)

[PDF]ESPECIFICAÇÃO TÉCNICA DE MATERIAL ETM - 003: DORMENTES ...
www.dnit.gov.br/.../especificacoes...dormentes.../ETM - 00....

ETM-003 : 1. ESPECIFICAÇÃO TÉCNICA DE MATERIAL. ETM - 003: DORMENTES. 1. OBJETIVO. Esta especificação tem por objetivo estabelecer as diretrizes básicas para a aquisição de dormentes. Define os diferentes tipos de dormentes, além de critérios e controle de recebimento, e critérios de medição e pagamento.
[PDF]ETS - 004 - Assentamento de Dormentes e Fixações.pdf - Dnit
www.dnit.gov.br/.../especificacoes...dormentes.../ETS - 004... - Translate this page
ETS-004 : 1. ESPECIFICAÇÃO TÉCNICA DE SERVIÇO. ETS - 004: ASSENTAMENTO DE DORMENTES E FIXAÇÕES. 1. OBJETIVO. Esta especificação tem por objetivo estabelecer as diretrizes básicas para a execução do serviço de assentamento de dormentes e fixações em obras ferroviárias. Define critérios e controle ...

Railroad tie
Wooden ties are used on many traditional railways. In the background is a track with concrete ties.
A railroad tie/railway tie/crosstie (North America) or railway sleeper (Britain, Ireland, South Asia, Australasia, and Africa) is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge.

Railroad ties are traditionally made of wood, but pre-stressed concrete is now also widely used, especially in Europe and Asia. Steel ties are common on secondary lines in the UK;[1] plastic composite ties are also employed, although far less than wood or concrete. As of January 2008, the approximate market share in North America for traditional and wood ties was 91.5%, the remainder being concrete, steel, azobé (red ironwood) and plastic composite.[2]

Approximately 3,520 wooden crossties are used per mile of mainline railroad track in the US (distance between ties is nominally 18" including one tie and the crib), 2,640 per mile (30 per 60 ft rail) on main lines in the UK. Rails in the US may be fastened to the tie by a railroad spike; iron/steel baseplates screwed to the tie and secured to the rail by a proprietary fastening system such as a Vossloh or Pandrol are commonly used in Europe.

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Note added at 4 hrs (2018-03-24 17:18:09 GMT)
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How to Fix Railway Sleepers?
www.rail-fastener.com › News
Ballast lies on subgrade and under rail sleeper to fix and protect the sleeper. Before paving the rail sleeper, it should first lay the ballast belt onto the subgrade evenly and flatly. During paving, the midline of sleeper must be perpendicular to the railroad midline, and the end that close to the sidewalk should place neatly.


Just to see the process:

https://www.railway-technology.com/features/feature92105/

https://en.wikipedia.org/wiki/Concrete_sleeper

https://www.youtube.com/watch?v=aG4sd9yRBD0

https://www.youtube.com/watch?v=_MKcTbYDP7w