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Train Tunnel and Tracks Expansion Set — LEGO set 10425

Official LEGO® image · © LEGO Group and/or the respective rights holders. Source: LEGO Italy ↗

DUPLO · SET 10425

Train Tunnel and Tracks Expansion Set

A grey tunnel and additional track extend an existing DUPLO railway.

Pieces
20
Release year
2025
Theme
DUPLO
Set number
10425
LEGO recommended age
2+
LEGO retail price · Italy
19.99 €
View on LEGO Italy Official building instructions

Retail price reported by the LEGO source for the stated market. Check the store for current price and availability; this does not establish the launch price. LEGO ↗ · Reference checked on 26 October 2026

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Official English name verified at: LEGO English catalogue ↗ · Checked on 26 October 2026.

TIME TO BUILD

How long does it take to build Train Tunnel and Tracks Expansion Set?

First build · with help if needed

For younger children, we estimate the first illustrated setup, with adult guidance when needed. Ranges reflect building familiarity, not a child’s age or ability. Free play and learning have no completion time.

Editorial estimate · first setup

Beginner

≈ 12 minSuggested range7 min – 20 min

Intermediate

≈ 8 minSuggested range4 min – 13 min

Experienced

≈ 6 minSuggested range3 min – 10 min

First guided arrangement: one model for 3 in 1 sets, a small composition for creative boxes, and setup alone for expansions. Excludes play, breaks and electronic configuration. These are broad editorial estimates, not measured times or targets to meet.

How we estimate times · sources and method

Editorial assessment of the first illustrated arrangement: A grey tunnel and additional track extend an existing DUPLO railway. This is an infrastructure expansion, not a complete train set; the estimate covers its setup. For creative boxes this means one first small composition, for 3 in 1 sets only the main model, and for expansion sets their setup. An adult may guide the child. Ranges reflect building familiarity, not age or development; they do not measure play, learning or a speed contest. No verified timed build: indicative values with substantial variation.

Sources do not always specify the builder’s experience. The three experience bands are our editorial assessment, based on the complexity of the set and individual accounts where available.

Checked: 26 October 2026 · Method v1.0 · Limited reports; not a statistical average.

Share your building time · no account needed

Include normal piece searching and instruction checks; exclude long breaks, dismantling and modifications.

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MAKE ROOM FOR YOUR NEXT BUILD

How much display space does it need?

Assembled-model dimensions are not yet documented for this set. Box dimensions cannot tell you how much display space it needs.

BEYOND THE BRICKS

Did you know?

The model, the history, the ideas

Inside the set

01

Through the tunnel

The arch creates a recognisable covered passage along the track.

LEGO source
02

An addition to the railway

This is an infrastructure expansion, not a complete train set; the estimate covers its setup.

LEGO source

Beyond the set

The stories, places and inventions behind your build.

03

Timetables changed time

As Britain’s railways expanded, timetables began following Greenwich time instead of local times that differed between towns.

Read the full story

Local town times made coordination across a railway network difficult. Royal Museums Greenwich connects the spread of GMT-based timetables in the 1840s with the need for a shared reference. Railways changed not only journeys, but how people compared clocks.

Royal Museums Greenwich
04

A London line from 1836

The London Bridge–Greenwich railway opened in 1836 as London’s first suburban line.

Read the full story

London Bridge opened in 1836, while the Greenwich end initially used a temporary station. A permanent brick building followed in 1840. Museum archives also preserve unrealised extension plans: the network grew through openings, temporary arrangements and revised ideas rather than one finished masterplan.

Royal Museums Greenwich

Expanded stories updated on 29 October 2026

Written by HowLongToBuild · Sources are linked with each story · Checked on 26 October 2026. Historical facts and story details refer to the context described.

THE COMMUNITY’S EXPERIENCE

What was it like to build?

Three separate scores from 1 to 10. For difficulty, 1 means very easy and 10 means very difficult.

No approved ratings yet. Scores are never generated by this site or inferred from the recommended age.

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Building tips from the community

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SET THE MOOD

A soundtrack for your build

· Selected for the subject and atmosphere

Penguin Cafe’s acoustic interlocks offer movement and returning patterns for a vehicle build. This light rhythmic choice follows the pleasure of assembling shapes and mechanisms without setting a pace for your hands.

Editorial suggestions, not official soundtracks for the set. External services may require an account or subscription; editions and availability can vary by country. Suggest another soundtrack →

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YOUR NEXT BUILD

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