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10K Club Interview: Union Pacific "Big Boy" by Lasse Hvidtfeldt

All aboard, Union Pacific "Big Boy" departing from Vejle has arrived to the LEGO Ideas 10K Club! Lasse Hvidtfeldt aka Lassehfl has taken on the immense task of recreating a displayable version of the biggest steam trains ever built. Show some support for the "Big Boy" in the comments!



  1. Who are you?
    Lasse Hvidtfeldt.

  2. Where are you from?
    I’m from Vejle in Denmark. 
  3. How old are you?
  4. What do you study or do for a living?
    I’m a part-time barista and I have my own production company. I plan on studying graphic design this summer. 
  5. What hobbies do you have?
    Quite a few. LEGO building, obviously. I find creating stuff in LEGO super challenging and satisfying. For the past 6-7 years I’ve been developing my skills as a photographer and videographer, mainly as a hobby until 1st of March this year, when I started my own production company. Moreover, graphic design has always interested me and I plan on taking this to the next level soon! 
  6. Have you created any LEGO MOCs (my own creations) that you’re particularly proud of? What is it, why are you proud of it and do you have a photo of it?
    The Big Boy train is actually my first MOC.
  7. How and when did your interest in LEGO come about?
    I honestly don’t remember when. It has just always been a part of my life. Like many others I took a break from LEGO in my teenage years. Thanks to Covid lockdown last year I decided to break down my older sets and sort them for the purpose of getting into the whole MOC game. And here we are 2 years later.
  8. What is LEGO for you? What does it mean for you? How does it fit in your life? E.g. build, display, meetups, play the games or 'just' watch the cartoons.
    LEGO products have taken quite a turn lately, towards the adult audience. I think this is awesome. It means that LEGO designers are now pumping out complex and beautifully detailed display models. I guess I’ve always been more into bigger display models than playsets, so the direction LEGO has taken is perfect for me. I have bought more LEGO sets this past year then I have the past 5 years. Just because the models are soooo goooood!
  9. What is your favourite LEGO theme (current or past)? Why? And has any theme inspired your building style or preference in any particular way?
    Creator Expert. I love realistic models. When I was younger, most of my sets were LEGO city, which I kind of funny considering all the big and colourful space-ninja-monster-fantasy LEGO sets which have been produced over the years. There is just something about that yellow bus from the pizzeria set.
  10. What is your favourite official LEGO set ever? Why?
    The creator expert Boeing 787 from 2006. I was 6 years old when it came out, and remember being on vacation in New York. I had my trusty LEGO magazine by my side at all times (I literally slept with it by my side), always opened at the double-sided Boeing 787 ad. It’s still just such an awesome and huge model! 
  11. What is your favourite LEGO element? Why?
    How could I possibly answer this…?
  12. Is there a LEGO designer (official LEGO designer or fan designer) who you are inspired by and look up to? Who and why?
    Apparently, LEGO designers love coffee, I’ve met a few in my short time at the coffee shop. Honestly, I don’t really know any LEGO designers other than Søren Dyrhøj who hosted the Danish LEGO Masters, and Matthew Ashton. They both just seem like really nice guys, and that I believe is the most important skill in life. 
  13. Is there one or more particular LEGO-related websites (not official LEGO websites) that you visit often and/or are inspired by?
    I probably spend more time ordering bricks on Bricklink than designing the model.



  1. Where did your interest in this particular model come from?
    My grandfather worked for the Danish State Railways so that must’ve passed on to my dad and from him onto me. My dad used to take me to train museums, model train conventions and he even built a model train track in our basement. So, I guess trains have always been a part of my life. The U.P. Big Boy in particular had me interested because of the sheer size and power. It is the biggest steam train ever produced, which makes it relevant as a LEGO set since the release of the LEGO Titanic model. I wanted to make this specific train ever since my dad bought a functioning scale model of it. 

  2. How long was the process of making the project did, and what did you have to research as well. What kind of prep, research and design phases did you go through to produce your creation?
    I spent well over 200 hours from start to finish. The process went something like: design, upload to ideas, order parts, make instructions, assemble, disassemble, redesign, reupload to ideas, order more bricks, make instructions again, assemble once more. Before designing, I had to gather references. As I mentioned, I have a scale model from Märklin which is super detailed and a great reference. So, I just went in and built every major detail with LEGO bricks. The hardest part was the inside, but I made it work. The research part wouldn’t come into play until I posted on Ideas, where the description had to be accurate. 
  3. What special challenges did you face creating the model? What was the most difficult part to recreate?
    Making it fit the standard curved LEGO tracks. It is a lot of wheels. Also motorizing it turned out to be quite a challenge as the power functions elements take up a lot of space on the inside. 
  4. If you could talk to yourself before you started on this project, what would you tell him? What do you know now that you wish you knew then? 
    “Maybe test the wheelsets before ordering the remaining 653789 pieces…”  
  5. How long did it take to complete the model? Did you finish it fairly quickly, or did it take a long time? And how did the build time compare to the time you spent promoting your Product Idea to reach 10,000 supporters?
    Well, since I didn’t promote it, I guess that makes it 0/100 promo/build time. Did I finish it quickly? Absolutely not. Had to spend the lockdown on something.
  6. How did it feel when you reached the magic 10,000 votes and how long did it take?
    It felt FANTASTIC! It took little more than 6 months and I kept track every single day. Weirdly enough every Monday I would get a huge boost in supporters. I guess people need some cheering up on Mondays. 
  7. Approximately how many LEGO bricks did you use to create your model?
    2656. Specifically. Fun fact, the building instructions contain 762 steps. I had to check every single step.
  8. What is your favourite building technique or part/section that you’ve incorporated into your Product Idea?
    The grey panel near the cabin uses the studs to mimic the real-life studded surface. And generally, how well all the studs are hidden.

  9. If you built your model digitally, what software did you use to build and render your model?
    Bricklink is just a crazy powerful tool. The renders it can produce are so crisp and photoreal.  
  10. If you used custom stickers or prints for your design, how did you create them or where did you get them?
    Stickers are made in Bricklink Part Designer. I’m still trying to figure out how to get them in real life. Suggestions are welcome in the comments below!



  1. Do you have any useful advice about creating a successful LEGO Ideas project?
    Don’t do it for the votes. Do it for the comments. The LEGO community is incredible. If you are passionate about your idea, chances are that other people will be too. Other than that, spend your time. Don’t rush the process - enjoy it.

  2. What (if any) methods did you use to advertise and attract support to your Product Idea? 
    None. I let it live its own life. Apparently, it worked. 
  3. What is your favourite LEGO Ideas Product Idea (besides your own of course)? Are there any Product Ideas you think have been overlooked?
    That’s an unfair question. Everyone on LEGO Ideas is SO TALENTED!
  4. What is it about the platform that attracts you? What tips would you give to anyone who is thinking about uploading an idea?
    The community. The people here are so nice and inspirational. Sometimes I just sit for hours scrolling through ideas, gathering inspiration. You should try that too. Oh, and don’t try to be too serious. LEGO building is fun. Remember that.
  5. Do you have plans to submit any other Product Ideas in the future? If yes, can you give us a hint of what that might be?Absolutely yes. Well, after making the Big Boy, any train should be easy. But no, I don’t know what the next model will be, so maybe consider following me in the community. 
  • 10k club
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  • lasse hvidtfeldt
  • union pacific big boy
  • lassehfl

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