  Formal methods and supporting tools have a long record of successes in the
development of safety-critical systems. However, it cannot be said that a
single tool has emerged as the dominant solution for system design. Each tool
differs from the others in terms of modelling language used, verification
capabilities and other complementary features, and each development context has
peculiar needs that require different tools. This is particularly problematic
for the railway industry, in which formal methods are highly recommended by the
norms, but no actual guidance is provided for the selection of tools. To guide
companies in the selection of the most appropriate formal tools to adopt for
their contexts, a clear assessment of the features of the available tools is
required. To address this goal, this paper considers a set of 14 formal tools
for system design, and presents a systematic evaluation of the tools and a
usability analysis with practitioners. Results are discussed considering the
most desired aspects by industry and previous related work. The focus is on the
railway domain, but the overall methodology can be applied to similar contexts.
Our study contributes with a systematic evaluation of formal tools and shows
that despite the poor graphical interfaces, usability and maturity of the tools
are not major problems, as claimed by other works. Instead, process integration
support is the most relevant pain point for the majority of the platforms.
