This was David's email to fbb a couple of weeks ago.
The third interchange line is metro 1 (yellow).
A fifth metro line is planned and shown in outline on the map above.
The North-south regional rapid railway is a railway construction plan in Budapest, modelled on the Paris RER or German S-Bahn systems. Its aim is to connect three of the Budapest Helyiérdekű Vasút (BHÉV) suburban train lines, from Szentendre, Ráckeve and Csepel. The plan is also called Metro 5.
This funicular rail was the second in Europe, only Lyon had a similar transportation system at that time. During the Second World War the cars and the terminals were destroyed by bombs. The remnants of the funicular were then dismantled. Replacement with escalators was considered later. Reconstruction of the funicular was decided in 1965, and several plans were made, but the construction works were delayed. A midibus service between the two termini (line "V") was launched in 1975. This was in operation until the line was finally reopened in 1986.
But that is for tomorrow's blog.
In the meantime, fbb notes that Budapest also has a significant trolleybus network ...
The Childrens' Railway.
The Gyermekvasút (English: Children's Railway) or Line 7 is a narrow gauge railway line in Budapest, which connects Széchényi-hegy and Hűvösvölgy and is 11.2 km long. Except the train driver, all of the posts are operated by children aged 10–14 under adult supervision. It is the world's largest Children's Railway.
What is even better; you can ride the "cogwheel railway" (line 60) to its outer terminus at Széchenyihegy ...