I believe there are a few north bound trains from Bangkok each day, and the one we took was due at the Don Muang train station at 1206 hours (it came half an hour late). It was a 3rd class ticket we bought, for 24 baht/person. No seats are guaranteed but you would most likely get one as people alight along the way.
Do bring a sweater as it could get chilly due to the speed of the train.
The train station is conveniently located in the old town about a 5-10 minute walk away from the hotels. All northern line trains depart from Bangkok's Hualamphong Train Station stop here and take about 3 hours or so. I came from Ayutthaya on the train which only took 45 minutes and cost just 20 baht in 3rd class. For more information on timetables and fares, check out the website below:
A cheap way to get to Lopburi is by 3rd class train .However journey back in the evening is really uncomfortable & a boring ride. Especially after along day touring the sunflower fields.Are we there yet?
The old city from Lopburi bus station you can reach by any city bus going that direction. Just stop the bus and ask if they are going to old city. When you will see the first ruins with monkeys, you will know you are entering old city.
It seems like all the buses we could take outside Lop Buri Inn Hotel all head towards the city centre. It was just a 10 minute journey, and costs a flat 5 baht no matter where you travel to.
An interesting note is that the bus conductor will "jump" off the bus before it stops and shouts to potential passengers their route (i think) and usually is the last to get up the bus too. They all seem to be operated by different families, and no fixed schedule but they come frequently enough, every one less than 5 minutes wait each time.
However, once the night sets in, they are nowhere to be seen, and even forced us to take the motorbike taxi back to our hotel. So please do check when they end their service each day.
Another thing to note is that they almost always have their favourite Thai music blaring in the back, so try to sit in the front, or where they don't have speakers.
Lopburi is easy to get to from Bangkok because you can choose to travel either by bus or train.
It is about a 150 km trip to Lopburi and takes about 2.5-3 hours, less if you board the bus or train in Don Muang part of Bkk. Buses depart Bkk from the northern bus terminal (Morchit Mai), trains from Hualampong and a few other locations along the line up to Don Muang.
The 3rd class train is probably the cheapest way to go, costing about 25 baht. Express trains are more but often don't get you there any faster.
The orange 'tamada' buses are also very cheap but be warned - no A/C and NO knee-room. Then there are 2nd and 1st class buses which cost a bit more, but are still very affordable for most travelers (around 100 baht).
In Lopburi, the bus terminal is at the Sakaew traffic circle. 1st class buses (A/C and toilet included) depart for Bkk every 20 minutes, 5 am to 8 pm. The irritating thing about the bus is that it will stop and pick up anyone standing at the side of the road - even if the bus is already packed - all the way to Saraburi, about 50 km. That is nice though you are at the side of the road..
The trains are less regular but a better way to see the countryside by far.
The train station is on the edge of the old part of the city and passes by many ruins, some that are so ruined you wouldn't know that they were once ruins.
Lopburi is on the northern railway line, so you can hop the train to get you up to Chiangmai if you want. If you want a sleeper, you will have to book ahead.